1、Designation: E1336 11 (Reapproved 2017)Standard Test Method forObtaining Colorimetric Data From a Visual Display Unit bySpectroradiometry1This standard is issued under the fixed designation E1336; the number immediately following the designation indicates the year oforiginal adoption or, in the case
2、 of revision, 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.INTRODUCTIONThe fundamental procedure for characterizing the color and luminance of a visual display uni
3、t(VDU) is to obtain the spectroradiometric data under specified measurement conditions, and fromthese data to compute CIE chromaticity coordinates and absolute luminance values based on the 1931CIE Standard Observer. The considerations involved and the procedures to be used to obtain precisioncolori
4、metric data for this purpose are contained in this test method. The values and procedures forcomputing CIE chromaticity coordinates are contained in Practice E308. The procedures for obtainingspectroradiometric data are contained in Test Method E1341. This test method includes somemodifications to t
5、he procedures given in Practice E308 that are necessary for computing the absoluteluminance values of VDUs. This procedure is intended to be generally applicable to any VDU device,including but not limited to cathode ray tubes (CRT), liquid crystal displays (LCD), and electrolu-minescent displays (E
6、LD).1. Scope1.1 This test method prescribes the instrumental measure-ments required for characterizing the color and brightness ofVDUs.1.2 This test method is specific in scope rather than generalas to type of instrument and object.1.3 The values stated in SI units are to be regarded asstandard. No
7、other units of measurement are included in thisstandard.1.4 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-priate safety and health practices and determine the applica-bilit
8、y of regulatory limitations prior to use.1.5 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recom-mendations issued by the Worl
9、d Trade Organization TechnicalBarriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:2E284 Terminology of AppearanceE308 Practice for Computing the Colors of Objects by Usingthe CIE SystemE1341 Practice for Obtaining Spectroradiometric Data fromRadiant Sources for Colorimetry2.2
10、 CIE Publications:Publication CIE No. 18 Principles of Light Measurements3Publication CIE No. 15.2 Colorimetry, 2nd ed., 19863Publication CIE No. 63 Spectroradiometric Measurement ofLight Sources, 198432.3 IEC Publications:Publication No. 441 Photometric and Colorimetric Methodsof Measurement of the
11、 Light Emitted by a Cathode-RayTube Screen, 197443. Terminology3.1 The definitions of appearance terms in TerminologyE284 are applicable to this test method.1This test method is under the jurisdiction of ASTM Committee E12 on ColorandAppearance and is the direct responsibility of Subcommittee E12.06
12、 on Display,Imaging and Imaging Colorimetry.Current edition approved May 1, 2017. Published May 2017. Originallyapproved in 1991. Last previous edition approved in 2011 as E1336 11. DOI:10.1520/E1336-11R17.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer
13、Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Available from CIE (International Commission on Illumination), http:/www.cie.co.at or http:/.4Available from International Electrotechnical Commission (IE
14、C), 3 rue deVaremb, Case postale 131, CH-1211, Geneva 20, Switzerland, http:/www.iec.ch.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United StatesThis international standard was developed in accordance with internationally recognized principles
15、on standardization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.14. Summary of Test Method4.1 Procedures are given for obtaining spectroradiometri
16、cdata and for the calculation of CIE tristimulus values and othercolor coordinates to describe the colors of VDUs. Modifica-tions to the standard calculation procedures of Practice E308are described.5. Significance and Use5.1 The most fundamental method for obtaining CIE tris-timulus values or other
17、 color coordinates for describing thecolors of visual display units (VDUs) is by the use ofspectroradiometric data. (See CIE No. 18 and 63.) These dataare used by summation together with numerical values repre-senting the 1931 CIE Standard Observer and normalized to Km,the maximum spectral luminous
18、efficacy function.5.2 The special requirements for characterizing VDUs pos-sessing narrow or discontinuous spectra are presented anddiscussed. Modifications to the requirements of Practice E308are given to correct for the unusual nature of narrow ordiscontinuous sources.6. Requirements When Using Sp
19、ectroradiometry6.1 When describing the measurement of VDUs byspectroradiometry, the following must be specified:6.1.1 The radiometric quantity determined, such as theirradiance (W/m2) or radiance (W/m2-sr), or the photometricquantity determined, such as illuminance (lm/m2) or luminance(lm/m2-sr or c
20、d/m2). The use of older, less descriptive names orunits such as phot, nit, stilb is not recommended.6.1.2 The geometry of the measurement conditions,including, whether a diffuser was used and the material fromwhich it was constructed, the distances from the VDU, the sizeof the area to be measured on
21、 the VDU, the uniformity of theVDU across the area to be measured, the microstructure of theVDU picture elements, and the presence of any specialintermediate optical devices such as integrating spheres.6.1.3 The spectral parameters, including the spectral region,wavelength measurement interval, and
22、spectral bandwidth.These must be specified since the various VDU technologiesmay demand more or less stringent requirements.6.1.4 The type of standard used to calibrate the system, astandard lamp, a calibrated source, or a calibrated detector, andthe source of the calibration.6.1.5 The physical and
23、temporal characteristics of the VDUincluding, refresh or field rate, convergence and purity adjust-ments (if the manufacturer allows such), luminance level, andany spectral line character in the emission from the VDU. Theintegration time of the detector system should be noted inrelation to the refre
24、sh or field rate of the VDU. (See IEC No.441.)7. Apparatus7.1 The basic instrument requirement is a spectroradiomet-ric system designed for the measurement of spectral radianceor irradiance of light sources. See Practice E1341 for details oneach of the parts of a spectroradiometer and how to calibra
25、teand use the instrument.7.2 Calibration Sources:7.2.1 The standard calibration source for spectroradiometryis a tungsten-filament lamp operated at a specified current. It ispreferable to have more than one standard lamp to permitcross-checks and to allow calibration at a range of luminancelevels.7.
26、2.2 Monochromatic emission sources such as a low-pressure mercury arc lamp or tunable laser should also beavailable for use in calibrating the wavelength scale.7.2.3 The electrical supplies for the calibration sourcesshould be of the constant current type. The supply should belinear and not a switch
27、ing supply. Current regulation should bemaintained to better than 0.1 %. At this level the radiant fluxfrom the calibration source is at least an order of magnitudemore stable than the flux from a VDU.7.2.4 There should be a standard for length measurementsavailable (such as a high quality metric ru
28、le) since absoluteirradiance calibration must be performed at an exact distancefrom the filament of the calibration lamp.7.3 Receiving OpticsTo maximize the light throughput thenumber of optical surfaces between the source of light shouldbe kept to a minimum. In extended diffuse sources (such asVDUs
29、) only a set of limiting apertures will be needed. In someinstances, it may be desirable to image the VDU with anintermediate focusing lens or mirror assembly. Care should betaken to use a magnification that will adequately fill theentrance slit when viewing both the calibration and test source.8. C
30、alibration and Verification8.1 Calibration and its verification are essential steps inensuring that precise and accurate results are obtained byspectroradiometric measurements. They require the use ofphysical standards, some of which may not be normallysupplied by commercial instrument manufacturers
31、. It remainsthe users responsibility to obtain and use the physical stan-dards necessary to keep his instrument in optimum workingcondition.8.2 Radiometric Scale:8.2.1 Zero Calibration or Its VerificationAll photometricdevices have some inherent photocurrent, even in the absenceof light. This so cal
32、led “dark current” must be measured andsubtracted from all subsequent readings either electrically orcomputationally.8.2.2 Radiometric Scale CalibrationA physical standardof spectral irradiance is normally used for calibration.After thedark current has been measured, the calibration source ispositio
33、ned in front of the receiving optics at the specifieddistance and operated at the specified electric current. Thisprovides a good approximation to a Plankian radiator acrossthe visible spectrum. The calibration source is measured andthe values of the dark-current-corrected photocurrent are re-corded
34、. These photocurrents are then related to the calibrationvalues of spectral irradiance that were provided by the stan-dardizing laboratory. The ratio of spectral irradiance to photo-current becomes the instrument calibration factor. All subse-quent measurements are multiplied by this ratio.E1336 11
35、(2017)28.2.3 Linearity VerificationPeriodically after the radio-metric and zero scale readings are established, the linearity ofthe scale should be verified.8.2.4 All calibrations should be performed using the sameintegration time constant that will be used during the measure-ment of the VDU.8.3 Wav
36、elength Scale:8.3.1 Scale Calibration and VerificationSince the outputof a cathode ray tube (CRT) type VDU contains some linestructure, the wavelength scale must be precise and accurateenough to characterize this line structure. Generally, the bestmethod of calibration or verification of the wavelen
37、gth scale isto determine the difference between the measured peaks, ormore preferably the wavelength centroids, and the tabulatedpositions of the emission line of mercury or neon arc lamps.Most monochromators exhibit significant nonlinear errors inaddition to the random linear errors. Generally, the
38、 best methodof either calibration or verification of the wavelength scale is todetermine the differences between the measured peaks and thetabulated positions of the emission lines of the arc lamps. Thedifferences should be averaged and reported. Random errorslarger than 1.0 nm should be cause for c
39、oncern.9. Procedure9.1 Selection of Measurement Parameters:9.1.1 If the VDU is small or highly directional so that thesolid angle subtended by the instrument aperture is a largefraction of the VDU area then measure the spectral irradiance.If the VDU is large, then measure the spectral radiance. Util
40、izethe appropriate calibration source. Mount all pieces of theapparatus solidly in place. An optical table or bench is highlyrecommended.9.1.2 Select the spectral region, measurement interval, inte-gration time constant and the spectral bandwidth (if possible).Try to keep the spectral bandwidth and
41、measurement intervalequal. The bandwidth should be no greater than 5.0 nm. ForVDUs with narrow band emitters, such as the P22 red CRTphosphor, the spectral bandwidth should be less than 2.0 nm.(See IEC No. 441.) The default spectral region should be 380to 780 nm. This region may vary slightly depend
42、ing on thetechnology of the VDU being characterized. It is unnecessaryto scan a VDU in a spectral region where there is no radiantoutput but the actual extent of region should be determinedexperimentally.9.1.3 Place the calibration source at the specified distancefrom the monochromator entrance aper
43、ture. Measure the VDUat the identical distance from the monochromator entranceaperture.9.2 Selection of Computational Parameters:9.2.1 Depending on the geometry of the measurements,select either radiance or irradiance calculations. Determine ifcorrelated color temperature calculations are required a
44、nd usethe correct CIE chromaticity coordinates and formulae for thecalculations, the 1960 uniform chromaticity scales and the1931 CIE color matching functions are the correct choices.5Use Km= 683 lm/W for the maximum spectral luminousefficacy. Note that neither luminance nor color temperature aredef
45、ined in terms of the 1964 CIE Supplementary StandardObserver.9.2.2 Practice E308 indicates that CIE tristimulus values areto be normalized by a constant that is calculated for theilluminant-observer pair. Here, the VDU is both the object andthe source of light. To calculate CIE absolute tristimulusv
46、alues, multiply each spectroradiometric reading (in Watts) bythe value of a CIE 1931 color matching function (x, y,orz) forthat wavelength. Sum these products over all wavelengths foreach of the color matching functions. (See CIE No. 15.2.)Multiply the sum by Km, the maximum spectral luminousefficac
47、y, which equals 683 lm/W.9.3 Measurements:9.3.1 Determine the zero scale first. This can be done eitherby scanning the spectral region with the entrance slit blockedand subtracting the reading from subsequent scans, or bymanually adjusting the radiometer to read zero when theentrance slit is blocked
48、.9.3.2 Scan the calibration source and determine the systemsspectral calibration factor by ratioing the tabulated spectralradiance (irradiance) values to the measured photocurrent.9.3.3 Replace the calibration source with the VDU and scanthe test source using the same settings. Multiple the readings
49、by the spectral calibration factor, wavelength by wavelength.9.3.4 For many radiometric measurements, the unknownphase relationship between the integration period of the spec-troradiometer and the field refresh rate of the VDU dominatesthe measurement error. Two alternative measurement tech-niques are suggested. First one could synchronize the radiom-eter integration time interval with the VDU refresh cycle andthen integrate for an integral number of refresh cycles. Second,one can integrate for a large number of refresh cycles thatexceed the inverse o
