1、Designation: F 2359 04Standard Test Method forDetermining Color of a Membrane Switch Backlit withDiffuse Light Source1This standard is issued under the fixed designation F 2359; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the y
2、ear of last revision. 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 This test method covers procedures for determining theluminous color of a backlit membrane switch. As written,
3、 itapplies to a fully assembled switch. For specific purposes, itcan be applied to partially assembled switches, with theunderstanding that the results pertain only to the partialassembly and will be modified as the further assembly pro-ceeds.2. Terminology2.1 Definitions:2.1.1 graphic overlaya grap
4、hically illustrated layer, oftenattached to the top side of the switch assembly for protection,cosmetic purposes, or to indicate the location and function ofthe switch keys.2.1.2 illumination layera layer in the construction of amembrane switch, which may or may not be a physicallydistinct layer whi
5、ch contains or supports the source of illumi-nation for the switch. Examples are a flexible layer containinglight emitting diodes (LEDs), often either the top or bottomlayer of the switch, or a flexible layer of electroluminescent(EL) material, often a distinct and separate layer added atassembly.2.
6、1.3 membrane switcha momentary switching device, inwhich at least one contact is on, or made of, a flexiblesubstrate.2.1.4 UUTunit under test.3. Significance and Use3.1 Illumination of a switch or of certain features of a switchoften has a functional purpose and must meet specification tosatisfy the
7、 functional requirements of the switch.3.2 Illumination of the switch can be affected by variationsin the quality and design of the overlay and its application.3.3 This test method addresses only the optical and visualappearance of the switch and not its electrical function.3.4 This test method is n
8、on-destructive.3.5 If this test method is applied to the entire switchassembly, the results can be applied to the whole device.However, it may be sufficient and practical to apply the testeither to a subassembly only, or to the illumination only, inwhich case the results apply to that layer only and
9、 the net effecton the fully assembled device must be extrapolated.4. Interferences4.1 Tests on incomplete assemblies give results appropri-ately to that state of assembly. Specifically, later application ofa graphic overlay may alter the results.4.2 Failure to fill the sampling aperture of the color
10、imeterwill bias the results in a way which is not necessarilypredictable and for which compensation cannot be made.4.3 Since every light source changes characteristics as itages, it must be recognized that the results apply to a particularinterval in the lifetime of the system. Characterization of t
11、heaging properties may be addressed in a separate test method.4.4 PerpendicularitySince the angular distribution ofemitted light can be altered by any material through which itpasses, it is important that photometer be held perpendicular tothe area to be sampled.4.5 TemperatureSince the performance
12、of many lightsources can vary with temperature, it is important to allow theUUT to thermally stabilize, if necessary, and then record theambient temperature at which the measurements are made.4.6 Ambient LightStray light sources will be detected bythe photometer and will affect UUT color measurement
13、 It isimportant to measure the ambient light before illuminating theUUT. This ambient light reading should be zero or as close tozero as possible.5. Apparatus5.1 A working or mounting surface to hold and support theUUT assembly, providing electrical access to the terminationregion from which the il
14、lumination is to be powered and visibleaccess to the regions at which the luminous color is to bemeasured.1This test method is under the jurisdiction of ASTM Committee F01 onElectronics and is the direct responsibility of Subcommittee F01.18 on MembraneSwitches.Current edition approved May 1, 2004.
15、Published June 2004.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.5.2 A power supply providing appropriate and adequatepower to drive the illumination device(s) with appropriateconnector(s). This should be specified as dc or ac, wi
16、th voltageand power level given, and ideally should be switched.5.3 A calibrated device to measure the color of the lumi-nance. This is typically a spot colorimeter or similar equip-ment, with a fairly compact sampling aperture (1-cm diameterat the minimum working distance). Output should be in one
17、ofthe CIE Tristimulus descriptions, such as the 1931 values (x, y)or the 1976 values (u, v).25.4 A means to support the color measuring instrument at afixed distance and orientation to the UUT.5.5 A means to control stray light and prevent it fromentering the aperture of the photometer.6. Procedure6
18、1 Mount UUT on the working surface with the luminoussurface visible.6.2 Attach a switched power source as appropriate to theluminous device set to the design operating point.6.3 Mount the colorimeter so that the axis of its field of viewis perpendicular to the area of the UUT to be measured. Ensure
19、that the sampling aperture is filled by the area to be measuredon the UUT.6.4 Measure the stray light level by taking a colorimeterreading while the UUT luminous source is not powered. If thisstep yields a significant measurement, do not proceed, but takesteps to reduce the stray light present. Unli
20、ke luminance orradiance (integrated spectrum) measurements, color measure-ments may not easily be compensated for the effects of straylight.6.5 Switch on the luminous source in the UUT assembly.6.6 Measure the color values of the UUT.7. Report7.1 Report the following information:7.1.1 State of UUT (
21、assembled or not),7.1.2 Stray light level,7.1.3 Color coordinates,7.1.4 Power conditions for the luminous device,7.1.5 Location and size of the sample area or areas,7.1.6 Colorimeter used, sample settings, calibration status,and the size of the sampling aperture,7.1.7 Ambient temperature, and7.1.8 D
22、ate of test.8. Keywords8.1 backlit; CIE; color coordinates; colorimeter; diffuselight; electroluminescent material; light emitting diodes; lumi-nance; luminous color; membrane switch; photometer; radiom-eter; video photometerASTM International takes no position respecting the validity of any patent
23、rights 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
24、any time 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
25、 will receive 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
26、 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).2For example, CIE Publication No.15.2, Colorimetry 2d ed., Central Bureau ofCIE, Vienna, 1986.F2359042
