ASTM F2429-15
(Terminology)Standard Terminology Relating to Aerospace Transparent Materials and Enclosures
Standard Terminology Relating to Aerospace Transparent Materials and Enclosures
SCOPE
1.1 These definitions cover generic optical terms which appear in one of more standards relating to aerospace transparent materials and enclosures.
1.2 The definitions cover, in most cases, special meanings used in the transparency industry. No attempt has been made to include common meanings of the same terms as used outside of the transparency industry.
1.3 Definitions included have, in general, been approved as standard.
General Information
Buy Standard
Standards Content (Sample)
NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation: F2429 − 15
Standard Terminology Relating to
1
Aerospace Transparent Materials and Enclosures
This standard is issued under the fixed designation F2429; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope a transparent material, which act like tiny mirrors that reflect
light in unwanted directions.
1.1 These definitions cover generic optical terms which
appear in one of more standards relating to aerospace trans-
design eye—the reference point in aircraft design from which
parent materials and enclosures.
all visual or optical anthropometrical design considerations
1.2 The definitions cover, in most cases, special meanings
are taken.
used in the transparency industry. No attempt has been made to
distortion—the rate of change of angular deviation across the
includecommonmeaningsofthesametermsasusedoutsideof
transparency, usually characterized by grid-line slope, result-
the transparency industry.
ing in the non-linear mapping of objects viewed through the
1.3 Definitions included have, in general, been approved as
transparency.
standard.
grid line slope—anopticaldistortionevaluationparameterthat
2. Terminology
compares the slope of a deviated grid line to that of a
non-deviated grid line, which is expressed as a ratio such as
2.1 Definitions:
angular deviation—the angular displacement of a light ray 1 in 8 or 1 in 20 (the visual optical quality improves as the
second number of the ratio gets larger).
from its original path caused by non-parallelism of opposite
surfaces as it passes through a transparent material, which is
halation—the scattering of light by the transparency into the
expressed in units of angle (degree, minutes of arc, millira-
viewer’s line-of-sight reducing the perceived contrast of
dians) and is a function of the angle of incidence at each
external objects, also referred to as haze.
surface of the material and the index of refraction of the
material.
haze—the percent of transmitted light that is scattered so that
its direction deviates more than a specified angle from the
angular displacement—the angular separation of the second-
direction of the incident beam, resulting in the reduction of
ary image from the primary image as measured from the
contrast of objects viewed through the transparency.
design eye position of a transparency.
binocular disparity—the difference in angular deviation be-
multiple imaging separation—the angular separation of pri-
tween two light rays passing through a transparency, origi-
mary and secondary multiple images as measured from the
nating from two eye positions located 2.5 in. apart.
design eye position.
birefringence—the separation of a light beam as it penetrates
rainbowing—colored patterns in a transparency produced by
a doubly refracting material into two diverging beams
the photo-elastic molecular nature of the material and stress
commonly known as ordinary and extraordinary beams,
gradients in the transparency in which certain angles and
which have been known to appear in transparencies as
light polarization
...
This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: F2429 − 05 (Reapproved 2010) F2429 − 15
Standard Terminology Relating to
1
Aerospace Transparent Materials and Enclosures
This standard is issued under the fixed designation F2429; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope
1.1 These definitions cover generic optical terms which appear in one of more standards relating to aerospace transparent
materials and enclosures.
1.2 The definitions cover, in most cases, special meanings used in the transparency industry. No attempt has been made to
include common meanings of the same terms as used outside of the transparency industry.
1.3 Definitions included have, in general, been approved as standard.
2. Terminology
2.1 Definitions:
angular deviation—the angular displacement of a light ray from its original path caused by non-parallelism of opposite surfaces
as it passes through a transparent material, which is expressed in units of angle (degree, minutes of arc, milliradians) and is a
function of the angle of incidence at each surface of the material and the index of refraction of the material.
angular displacement—the angular separation of the secondary image from the primary image as measured from the design eye
position of a transparency.
binocular disparity—the difference in angular deviation between two light rays passing through a transparency, originating from
two eye positions located 2.5 in. apart.
birefringence—the separation of a light beam as it penetrates a doubly refracting material into two diverging beams commonly
known as ordinary and extraordinary beams, which may have been known to appear in transparencies as rainbowing or the
apparent random dispersion of light into its component colors.
crazing—the occurrence of very small, localized, micro-cracks at or under the surface of, but not extending entirely through, a
transparent material, which act like tiny mirrors that reflect light in unwanted directions.
design eye—the reference point in aircraft design from which all visual or optical anthropometrical design considerations are
taken.
distortion—the rate of change of angular deviation across the transparency, usually characterized by grid-line slope, resulting in
the non-linear mapping of objects viewed through the transparency.
grid line slope—an optical distortion evaluation parameter that compares the slope of a deviated grid line to that of a non-deviated
grid line, which is expressed as a ratio such as 1 in 8 or 1 in 20 (the visual optical quality improves as the second number of
the ratio gets larger).
halation—the scattering of light by the transparency into the viewer’s line-of-sight reducing the perceived contrast of external
objects, also referred to as haze.
haze—the percent of transmitted light that is scattered so that its direction deviates more than a specified angle from the direction
of the incident beam, resulting in the reduction of contrast of objects viewed through the transparency.
multiple imaging
...
Questions, Comments and Discussion
Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.