ASTM F2359-04(2019)

This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: F2359 − 04 (Reapproved 2019)
Standard Test Method for
Determining Color of a Membrane Switch Backlit with
Diffuse Light Source
This standard is issued under the fixed designation F2359; 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 layer of the switch, or a flexible layer of electroluminescent
(EL) material, often a distinct and separate layer added at
1.1 This test method covers procedures for determining the
assembly.
luminous color of a backlit membrane switch. As written, it
applies to a fully assembled switch. For specific purposes, it 2.1.3 membrane switch—a momentary switching device, in
which at least one contact is on, or made of, a flexible
can be applied to partially assembled switches, with the
understanding that the results pertain only to the partial substrate.
assembly and will be modified as the further assembly pro-
2.1.4 UUT—unit under test.
ceeds.
3. Significance and Use
1.2 The values stated in SI units are to be regarded as
standard. No other units of measurement are included in this
3.1 Illuminationofaswitchorofcertainfeaturesofaswitch
standard.
often has a functional purpose and must meet specification to
1.3 This standard does not purport to address all of the satisfy the functional requirements of the switch.
safety concerns, if any, associated with its use. It is the
3.2 Illumination of the switch can be affected by variations
responsibility of the user of this standard to establish appro-
in the quality and design of the overlay and its application.
priate safety, health, and environmental practices and deter-
3.3 This test method addresses only the optical and visual
mine the applicability of regulatory limitations prior to use.
appearance of the switch and not its electrical function.
1.4 This international standard was developed in accor-
dance with internationally recognized principles on standard-
3.4 This test method is non-destructive.
ization established in the Decision on Principles for the
3.5 If this test method is applied to the entire switch
Development of International Standards, Guides and Recom-
assembly, the results can be applied to the whole device.
mendations issued by the World Trade Organization Technical
However, it may be sufficient and practical to apply the test
Barriers to Trade (TBT) Committee.
either to a subassembly only, or to the illumination only, in
which case the results apply to that layer only and the net effect
2. Terminology
on the fully assembled device must be extrapolated.
2.1 Definitions:
2.1.1 graphic overlay—a graphically illustrated layer, often
4. Interferences
attached to the top side of the switch assembly for protection,
4.1 Tests on incomplete assemblies give results appropri-
cosmetic purposes, or to indicate the location and function of
ately to that state of assembly. Specifically, later application of
the switch keys.
a graphic overlay may alter the results.
2.1.2 illumination layer—a layer in the construction of a
4.2 Failure to fill the sampling aperture of the colorimeter
membrane switch, which may or may not be a physically
will bias the results in a way which is not necessarily
distinct layer which contains or supports the source of illumi-
predictable and for which compensation cannot be made.
nation for the switch. Examples are a flexible layer containing
light emitting diodes (LEDs), often either the top or bottom 4.3 Since every light source changes characteristics as it
ages, it must be recognized that the results apply to a particular
interval in the lifetime of the system. Characterization of the
aging properties may be addressed in a separate test method.
This test method is under the jurisdiction of ASTM Committee F01 on
Electronics and is the direct responsibility of Subcommittee F01.18 on Printed
4.4 Perpendicularity—Since the angular distribution of
Electronics.
emitted light can be altered by any material through which it
Current edition approved Dec. 1, 2019. Published December 2019. Originally
passes, it is important that photometer be held perpendicular to
approved in 2004. Last previous edition approved in 2011 as F2359 – 04 (2011).
DOI: 10.1520/F2359-04R19. the area to be sampled.
Copyright © ASTM International, 1
...