1、Designation: F2771 10Standard Test Method forDetermining the Luminance Curve of an ElectroluminescentLamp at Ambient Conditions1This standard is issued under the fixed designation F2771; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revisi
2、on, the year 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 This test method establishes the procedures for deter-mining the visible performance change, which is
3、defined byluminance, color and cosmetic appearance of an electrolumi-nescent lamp during operation over an extended time.1.2 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-p
4、riate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2F1595 Practice for Viewing Conditions for Visual Inspec-tion of Membrane SwitchesF2359 Test Method for Determining Color of a MembraneSwitch Backlit wi
5、th Diffuse Light SourceF2360 Test Method for Determining Luminance of a Mem-brane Switch Backlit with Diffuse Light Source3. Terminology3.1 Definitions:3.1.1 luminance, nmeasure of the brightness or luminousintensity of light, usually expressed in units of candelas persquare metre (cd/m2) or foot la
6、mberts. 1 fL = 3.426 cd/m2.3.1.2 luminance curve, na graphical representation of thevariation of luminance with time (implicitly under unvaryingoperating conditions).3.1.3 electroluminescent lamp (EL lamp), nessentially acapacitor structure with phosphor and a dielectric sandwichedbetween electrodes
7、, one of which is transparent to allow lightto escape. Application of an ac voltage across the electrodesgenerates a charging field within the phosphor, which causes itto emit light.3.1.4 time to half luminance (THL), nthe elapsed operat-ing time over which the luminance of a lamp maintained underco
8、nstant power conditions is reduced to 50 % of its initialvalue.3.1.5 membrane switch, na momentary switching device,in which at least one contact is on, or made of, a flexiblesubstrate.4. Summary of Test Method4.1 This test method includes an initial measurement of theluminance, color, and appearanc
9、e of a lamp when poweredwith a specified voltage source. After initial characterization,the lamp is maintained under the same power conditions for anextended interval in a controlled environment designed tointerfere minimally with the operating characteristics of thelamp. The luminance, color and ap
10、pearance of the lamps undertest are measured and recorded at a predetermined schedulethroughout the test (initially the intervals are shorter to capturethe rapid rate of change and longer as the test progresses). Oneoutput of the measurement is to identify the time of operationby which the measured
11、luminance is reduced to half thatrecorded at the initial characterization.5. Significance and Use5.1 To provide a standardized test method that can be usedfor a valid comparison of luminance time curves, color changesand cosmetic changes between lamps of various designs,fabrication techniques, and s
12、ources.6. Interferences6.1 HumidityPerformance characteristics can be skewedwith the change of humidity.6.2 TemperaturePerformance characteristics can beskewed with the change of temperature.6.3 PowerPerformance characteristics can be skewedwith variations in the voltage, frequency and waveform of t
13、hepower applied to the lamp.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, 2010. Published June 2010. Originallyapproved in 2009. Last edition approved in 2009
14、 as F2771 - 09. DOI: 10.1520/F2771-10.2For 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 Interna
15、tional, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.7. Apparatus7.1 Power source capable of providing an appropriate acvoltage, frequency and waveform. For example, operation at110 6 3 VRMS, at 400 6 10 Hz, square wave which isprevalent in the industry.7.2 Lum
16、inance measurement equipment as specified in TestMethod F2360.7.3 Color measurement equipment as specified in TestMethod F2359.8. Hazards8.1 8.1 The procedure requires the verification of highvoltage ac power. Proper precautions against personal hazardsshould be followed.9. Preparation of Apparatus9
17、.1 A location should be established in which the lamp canremain while powered for the duration of the test, free frominterference and in an environment of subdued ambient light.The location should minimize interference from radianceproduced by other samples under test.10. Conditioning10.1 Test Condi
18、tionsIt is recommended that these tests beconducted in a standard laboratory atmosphere of 23 6 5Cand 50 6 10 % relative humidity, for the sake of uniformityand consistency. Any variance from these conditions shall benoted.10.1.1 Ambient life tests should be performed at a minimumof 40 % relative hu
19、midity. Dry atmospheres do not simulatetypical use conditions.10.1.2 Precondition lamp for a minimum of 12 h at tem-perature and humidity prior to initial measurement.10.1.3 Power supply settings for the lamp should be estab-lished and not varied throughout the test.11. Procedure11.1 Pre-Test Setup:
20、11.1.1 The test sample must be powered between 3 to 10min to allow the lamp to stabilize to test conditions and recordactual duration.11.1.2 Record date of the start of the test.11.2 Test Procedure:11.2.1 Mount EL lamp on a suitable test platform in a darkroom as outlined in Test Method F2360.11.2.2
21、 Identify test area that is blemish free for initialmeasurements.11.2.3 Before each measurement, inspect the lamp surfacefollowing Test Method F1595 to identify cosmetic blemishes,which might have occurred. Record the size and location of theblemishes. If blemishes appear in the test area of the lam
22、p: (a)further quantitative measurements can be made in the samearea and annotated to indicate the presence of a blemish, or (b)an adjacent area can be established for further use, if lampuniformity is sufficient (any such change should be reported inthe results), or (c) cancel the measurement series
23、 and begin testagain with a new sample. It is recommended that the entireseries of measurements be made without the inclusion of adiscrete blemish in the measurement area.11.2.4 Measure and record luminance and color of thelamps per Test Methods F2360 and F2359 regularly. Beforeeach measurement, ver
24、ify that the power applied remainsunchanged. Significant alteration of the driving waveform willalter the appearance and the aging characteristics of the lamp.The frequency of measurement should be sufficient to allow thegeneration of an accurate profile of the luminance decay overtime. It is sugges
25、ted that a luminance change between datapoints should be no more than5%oftheinitial luminance.11.2.5 For meaningful performance data the test is tocontinue until the luminance reaches any of the followingconditions:11.2.5.1 A luminance level that is 20-25 % of the initialluminance,11.2.5.2 Time to h
26、alf luminance (THL),11.2.5.3 A percentage of initial luminance, and11.2.5.4 Failure (absence of detectable luminance).12. Calculation or Interpretation of Results12.1 Performance Curve:12.1.1 Plot a luminance curve as a function of time. See Fig.1.FIG. 1 Luminance CurveF2771 10212.1.1.1 Identify THL
27、 on the curve. See Fig. 1.12.1.2 Record color coordinates when measuring lumi-nance.13. Report13.1 Report the following information:13.1.1 Date of manufacture of sample,13.1.2 Temperature,13.1.3 Humidity,13.1.4 Voltage, frequency and waveform of the powerapplied,13.1.5 Packaging and storage conditio
28、ns prior to test,13.1.6 Luminance curve, and13.1.7 Color coordinate data in tabular form as a function oftime.14. Precision and Bias14.1 Precision It is not possible to specify the precision ofthe procedure in Test Method F2771 for measuring the lumi-nous curve because inter-laboratory studies have
29、proven incon-clusive due to insufficient participating laboratories with theappropriate equipment.14.2 BiasNo information can be presented on the bias ofthe procedure in Test Method F2771 for measuring luminouscurve because no standard sample is available for this industry.15. Keywords15.1 aging; el
30、ectroluminescent; luminance; time to halfluminanceASTM International takes no position respecting the validity of any patent 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 right
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33、ou 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). Permission rights to photocopy the standard may also be secured from the ASTM website (www.astm.org/COPYRIGHT/).F2771 103
