1、Designation: F 2429 05Standard Terminology Relating toAerospace Transparent Materials and Enclosures1This standard is issued under the fixed designation F 2429; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revis
2、ion. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) 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-parent materials
3、 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 asstandard.2. Referen
4、ced Documents2.1 ASTM Standards:2D 1003 Test Method for Haze and Luminous Transmittanceof Transparent PlasticsF 1165 Test Method for Measuring Angular Displacementof Multiple Images in Transparent PartsF 1316 Test Method for Measuring the Transmissivity ofTransparent PartsF 2156 Test Method for Meas
5、uring Optical Distortion inTransparent Parts Using Grid Line Slope2.2 Other Document:AL-TR-1993-00363. Terminology3.1 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,
6、which isexpressed in units of angle (degree, minutes of arc, millira-dians) and is a function of 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
7、 thedesign eye position of a transparency.binocular disparitythe difference in angular deviation 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
8、into two diverging beamscommonly known as ordinary and extraordinary beams,which may appear in 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 ent
9、irely through,a transparent material, which act like tiny mirrors that reflectlight in unwanted 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 thetran
10、sparency, usually characterized by grid-line slope, result-ing in the non-linear mapping of objects 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 rati
11、o such as1 in 8 or 1 in 20 (the visual optical quality improves as thesecond number of the ratio 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
12、light that is scattered so thatits direction deviates more than a specified angle from thedirection 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 me
13、asured from thedesign eye position.rainbowingcolored patterns in a transparency produced bythe 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 co
14、lor in the transparency,often referred to as birefringence.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 Jan. 1, 2005. Published Januar
15、y 2005.2For 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.1Copyright ASTM International, 100 Barr Harbor Drive,
16、PO Box C700, West Conshohocken, PA 19428-2959, United States.scratchany marking or tearing of the 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 rati
17、o of the amount of radiantenergy leaving the last surface of an optical system to theamount of radiant energy incident on the first surface.ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this
18、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 time by the responsible technical committee and must be reviewed every five years
19、 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 receive careful consideration at a meeting of theresponsible technical committe
20、e, 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 International, 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).F2429052
