1、Designation: F 2771 09Standard Test Method forDetermining the Luminance Curve of an ElectroluminescentLamp at Ambient Conditions1This standard is issued under the fixed designation F 2771; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revi
2、sion, 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 i
3、s 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
4、-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2F 1595 Practice for Viewing Conditions for Visual Inspec-tion of Membrane SwitchesF 2359 Test Method for Determining Color of a MembraneSwitch Backli
5、t with Diffuse Light SourceF 2360 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 fo
6、ot lamberts. 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 elect
7、rodes, 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 un
8、derconstant 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 appe
9、arance 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 a
10、nd appearance 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 meas
11、ured 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,
12、and sources.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
13、 of thepower 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, 2009. Published June 2009.2For referenced ASTM standards, visit the ASTM websit
14、e, 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, PO Box C700, West Conshohocken, PA 19428-2959, United States
15、.7. Apparatus7.1 Power source capable of providing an appropriate acvoltage and frequency. For example, operation at 110 6 3VRMS, at 400 6 10 Hz, which is prevalent in the industry.Anydeviation shall be reported.7.2 Luminance measurement equipment as specified in TestMethod F 2360.7.3 Color measurem
16、ent equipment as specified in TestMethod F 2359.8. Hazards8.1 8.1 The procedure requires the verification of highvoltage ac power. Proper precautions against personal hazardsshould be followed.9. Preparation of Apparatus9.1 A location should be established in which the lamp canremain while powered f
17、or 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 ConditionsIt is recommended that these tests beconducted in a standard laboratory at
18、mosphere 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 humidity. Dry atmospheres do not simulatetypical use conditions.10.1.2 Preconditi
19、on 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:11.1.1 The test sample must be powered between 3 to 10min to allow the lamp to
20、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 F 2360.11.2.2 Identify test area that is blemish free for initialmeasurements.11.2.3 Before
21、 each measurement, inspect the lamp surfacefollowing Test Method F 1595 to identify cosmetic blemishes,which might have occurred. Record the size and location of theblemishes. If blemishes appear in the test area of the lamp: (a)further quantitative measurements can be made in the samearea and annot
22、ated 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 and begin testagain with a new sample. It is recommended that the entireseri
23、es 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 F 2360 and F 2359 regularly. Beforeeach measurement, verify that the power applied remainsunchanged. Significant alteration of the
24、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 suggested that a luminance change between datapoints should be no more than5%ofth
25、einitial 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 half luminance (THL),11.2.5.3 A percentage of initial luminance, and11.2.5.4
26、 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.1.12.1.1.1 Identify THL on the curve. See Fig. 1.12.1.2 Record color coordinates when measuring lumi-nance.13. Report13.1 Report
27、the following information:13.1.1 Date of manufacture of sample,13.1.2 Temperature,13.1.3 Humidity,13.1.4 Voltage and frequency of the power applied,13.1.5 Packaging and storage conditions prior to test,13.1.6 Luminance curve, and13.1.7 Color coordinate data in tabular form as a function oftime.14. P
28、recision and Bias14.1 The precision and bias of this test method are underinvestigation.15. Keywords15.1 aging; electroluminescent; luminance; time to halfluminanceF2771092ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentioned
29、in 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 any time by the responsible technical committee and m
30、ust 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 will receive careful consideration at a meeting of t
31、heresponsible 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 ASTM International, 100 Barr Harbor Drive, PO Box C7
32、00, 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).FIG. 1 Luminance CurveF2771093
