IESNA LM-58-2013 Approved Method Spectroradiometric Measurement Methods for Light Sources.pdf

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1、IES LM-58-13Approved Method: SpectroradiometricMeasurement Methods for Light SourcesIES LM-58-13IES Approved Method for Spectroradiometric Measurement Methods for Light SourcesPublication of this ApprovedMethod has been approved by the IES.Suggestions for revisionsshould be directed to the IES.Prepa

2、red by:The Sub-Committee on Photometry of Light Sourcesof the IES Testing Procedures CommitteeIES LM-58-13Copyright 2013 by the Illuminating Engineering Society of North America.Approved by the IES Board of Directors, September 3, 2013, as a Transaction of the Illuminating Engineering Society.All ri

3、ghts reserved. No part of this publication may be reproduced in any form, in any electronic retrieval system or otherwise, without prior written permission of the IES.Published by the Illuminating Engineering Society of North America, 120 Wall Street, New York, New York 10005.IES Standards and Guide

4、s are developed through committee consensus and produced by the IES Office in New York. Careful attention is given to style and accuracy. If any errors are noted in this document, please for-ward them to Rita Harrold, Director of Technology, at the above address for verification and correction. The

5、IES welcomes and urges feedback and comments. ISBN # 978-0-87995-284-6Printed in the United States of AmericaDISCLAIMERIES publications are developed through the consensus standards development process approved by the American National Standards Institute. This process brings together volunteers rep

6、resent-ing varied viewpoints and interests to achieve consensus on lighting recommendations. While the IES administers the process and establishes policies and procedures to promote fairness in the development of consensus, it makes no guaranty or warranty as to the accuracy or completeness of any i

7、nformation published herein.The IES disclaims liability for any injury to persons or property or other damages of any nature whatsoever, whether special, indirect, consequential or compensatory, directly or indirectly result-ing from the publication, use of, or reliance on this document.In issuing a

8、nd making this document available, the IES is not undertaking to render professional or other services for or on behalf of any person or entity. Nor is the IES undertaking to perform any duty owed by any person or entity to someone else. Anyone using this document should rely on his or her own indep

9、endent judgment or, as appropriate, seek the advice of a competent professional in determining the exercise of reasonable care in any given circumstances.The IES has no power, nor does it undertake, to police or enforce compliance with the contents of this document. Nor does the IES list, certify, t

10、est or inspect products, designs, or installations for compliance with this document. Any certification or statement of compliance with the requirements of this document shall not be attributable to the IES and is solely the responsibility of the certifier or maker of the statement.IES LM-58-13Prepa

11、red by the Subcommittee on Photometry of Light Sources of the IES Testing Procedures CommitteeSubcommittee on Photometry of Light SourcesGreg McKee, Sub-ChairWork GroupGreg McKee, Rolf Bergman, Cameron Miller, Eric Bretschneider, David EllisCameron Miller, LiaisonIES Testing Procedures CommitteeC. C

12、ameron Miller, Chair L. Ayers*R. BergmanE. Bretschneider*D. Chan*R. Daubach*J. Demirjian*P. Elizondo*S. Ellersick*D. EllisA. Gelder*P. Hung*A. JacksonD. Karambelas*T. Kawabata*T. Koo*M.KotrebaiJ. Leland*J. Linquata*R. Low*J. MarellaF. Morin*Y. Ohno*M. Piscitelli*B. Rao*M. SapcoeV. Wu*C. AndersenL. A

13、yers*A. Baker*R. BergerR. Bergin*R. BergmanJ. Blacker*E. BretschneiderK. Broughton*D. Chan*P. Chou*K. Curry*R. Daubach*L. Davis*J. Demirjian*D. Ellis*P. Franck*M. GratherY. Guan*K. Haraguchi*R. Heinisch*K. Hemmi*T. Hernandez*R. HoranJ. HospodarskyS. Hua*J. HulettP. HungD. Husby*A. JacksonD. Jenkins*

14、J. Jiao*D. Karambelas*H. Kashani*T. Kawabata*R. Kelley*T. Koo*M. KotrebaiB. Kuebler*J. Lawton*J. Lee*L. Leetzow*J. Leland*K. Lerbs*R. Levin*I. Lewin*R. Li*M. Lin*R. Low*M. Lu*J. MarellaP. McCarthyG. McKeeF. Morin*D. Nava*W. NewlandY. Ohno*D. Park*N. Peimanovic*G. Plank*E. RadkovD. Randolph*C. Richar

15、ds*E. Richman*K. Rong*M. SapcoeJ. SchutzA. Serres*A. SmithD. Smith*R. Speck*L. Stafford*G. SteinbergR. TuttleT. Uchida*K. Wagner*J. Walker*H. Waugh*J. Welch*K. Wilcox*B. Willcock*V. Wu*J. Yo nJ. Zhang*AdvisoryIES LM-58-13IES LM-58-13ContentsForeword .1Introduction.1Safety Precautions .11.0 Scope .22

16、.0 Normative references .23.0 Definitions and Nomenclature 24.0 Spectroradiometers 24.1 Characteristics24.1.1 Wavelength dispersion .24.1.2 Wavelength calibration .24.1.3 Bandwidth 24.1.4 Slit scattering function (bandpass function)34.1.5 Wavelength interval .34.1.6 Stray light .34.1.7 Input geometr

17、y.34.1.8 Calibration sources44.1.8.1 Spectral irradiance .44.1.8.2 Spectral radiance 44.1.8.3 Total spectral radiant flux 44.2 Array spectrometry 44.2.1 Design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54.2.1.1 C

18、CD array spectrometers54.2.1.2 Linear diode array spectrometers 54.2.2 Integration time 54.2.3 A/D converter data rate 54.2.4 Dynamic range.54.2.5 Signal to Noise (S/N) 64.2.6 Linearity 64.2.7 Dark measurements.64.2.8 Spectral resolution 64.2.9 Trigger capability .6IES LM-58-134.2.10 Wavelength accu

19、racy 64.2.11 Bandpass determination64.3 Scanning spectrometry.64.3.1 Continuous scanning 74.3.2 Sequential scanning.75.0 Detectors.75.1 General75.2 Ultraviolet-visible region (UV-VIS).85.2.1 Photomultipliers 85.2.2 Silicon photodiodes .85.2.3 Other photodiodes 85.3. NIR region .85.3.1 Germanium phot

20、odiodes .85.3.2 Indium gallium arsenide (InGaAs) photodiodes.85.3.3 Other NIR photodiodes.86.0 Correction Methods 86.1 Flicker and corrections .86.2 Bandpass correction .96.3 Stray light and stray-light correction 97.0 Calculations .107.1 Spectral radiometric quantities107.2 Radiometric quantities 1

21、07.3 Photometric quantities 108.0 Reporting Requirements .10References 11Informative References 111IES LM-58-13FOREWORDThis guide is a revision of IESNA LM-58-1994 IES Guide to Spectroradiometric Measurements. Significant changes have been made to update infor-mation to be representative of the curr

22、ent technolo-gies available, to give clearer guidelines for require-ments, and to promote uniformity and accuracy in spectroradiometric measurements. Also incorpo-rated in this revision is information formerly found in IES LM 55-96 IESNA Guide for the Measurement of Ultraviolet Radiation from Source

23、s, dealing with spectral measurements in the UV (ultraviolet) region.INTRODUCTIONIn evaluating the color performance of light sources, there are two factors to be considered: The light source color appearance (hue and saturation). The color rendering (the effect of the light source on the appearance

24、 of objects compared to their appearance under a reference source).The perceived color of a light source is its appear-ance apart from its luminance, geometry and time variations. This, in turn, depends upon the relative Spectral Power Distribution (SPD) of the radiant energy from the source and the

25、 observer adaptation. Two sources may have the same color appearance, and yet have entirely different relative spectral power distributions (i.e., they may produce a metameric match); but if they have the same relative spectral power distributions, they will have the same color appearance all other

26、factors being constant.The SPD constitutes the basic data needed for the computation of chromaticity coordinates and met-rics that describe color rendering. These data are obtained by spectroradiometry, whereby the light from the source is dispersed into its component wavelengths and the power in ea

27、ch narrow band of wavelengths is measured. Spectroradiometry has been practiced since Newton discovered the disper-sive properties of a prism on light. Spectroradiometry is now recognized as the most accurate, precise, and dependable method of determining chromaticity of any light source.Where visua

28、l phenomena such as color are involved, the SPD usually is determined between wavelengths of 380 nm to 780 nm, and should be measured at sufficiently narrow bandwidths to show the desired resolution. For more complete coverage the SPD should be determined between wavelengths of 360 nm to 830 nm. Oft

29、en, the curves are plotted at five-nanometer intervals, and are based on a spec-tral band pass of approximately five nanometers. Recently, computer plotted spectral power distri-butions have become common at intervals much smaller than five nanometers. For sources contain-ing line spectra, it has be

30、en found necessary for accurate resolution of spectra to utilize a band pass of approximately two nanometers. Obtaining luminous, chromaticity, and color render-ing values has been greatly simplified as the perti-nent calculations are now done by the application software, which operates on the SPDs

31、measured by the spectroradiometer. Sufficient accuracy is attainable with modern spectroradiometric systems so that they can be used for defining standards for other methods of colorimetry (e.g., with tristimulus colorimeters). In general, a spectroradiometer con-sists of a monochromator (dispersing

32、 instrument), a detector to measure the power at the output of the monochromator, and a device for recording data. A standard light source of known spectral power distri-bution is used for calibration.The spectroradiometric method is advantageous because once calibration has been carried out against

33、 one standard source (usually an incan-descent filament lamp), the spectroradiometer can determine-with equal accuracy-the SPD of light sources of any color, providing only that the unknown SPD is within the range of calibration. This range can comfortably run from 380 nm to 780 nm and more desirabl

34、e from 360 nm to 830 nm and, therefore, covers the visible region of interest for determining chromaticity.Safety PrecautionsSince overexposure to the bactericidal (germicidal) and erythemal ultraviolet radiation may result in erythema (reddening of the skin) or keratoconjunc-tivitis (inflammation o

35、f the cornea and conjunctiva, the exposed eye membranes), it is imperative that suitable eye protection and clothing be used when conducting measurements in these spectral regions. Lamp manufacturers recommendations for safety precautions should be followed.1Strong ultraviolet sources, such as deute

36、rium lamps, can produce ozone. Adequate ventilation should be maintained.2IES LM-58-131.0 SCOPEThis document describes the requirements and recommendations of the instruments and the pro-cedures for spectroradiometric measurements including those of color performance, spectral irradiance, spectral r

37、adiance, and spectral total radiant flux, either in relative or in absolute units. The spectral range is from approximately 200 nm to 1700 nm where the characterization of light from lighting sources, visual displays and light emitting diodes, is most commonly done. This document does not provide in

38、 depth detail on every subject, but directs the user to references that completely describe the concepts. The light source or device under test shall be operated in accordance with the appropriate IES LM (Lighting Measurement) or ANSI (American National Standards Institute) doc-ument pertaining to t

39、he device and is not described in this document.2.0 NORMATIVE REFERENCESNo normative references3.0 DEFINITIONS AND NOMENCLATUREBandwidth of a monochromator: The width between its half - peak of the slit scattering function 2.Colorimeter: an instrument designed for the mea-surement of the chromaticit

40、y of a light without deter-mining its SPD. It may give chromaticity coordinates directly, or by suitable calibration, give data that can be converted to these coordinates.Input optics of a monochromator: Refers to the optical elements placed between a light source and the entrance slit of the monoch

41、romator, to direct radiation of a light source to the monochromator.Slit scattering function (bandpass function): Relative spectral throughput of a monochromator or relative spectral responsivity of a spectroradiometer at a fixed wavelength setting.Total spectral radiant flux Wnm-1: The geometri-cal

42、ly total radiant flux in all directions (4 sr) from a source, at a given wavelength, per unit wavelength.4.0 SPECTRORADIOMETERS4.1 Characteristics4.1.1. Wavelength dispersion The monochroma-tor may be either a single-pass or double-pass instrument. The dispersing element(s) may be a prism, a diffrac

43、tion grating, or a combination of the two. Prisms are usually less expensive, but their dispersion varies with wavelength such that longer wavelengths are crowded closer together in the monochromator output. A uniform wavelength inter-val (band pass) is desirable for easy reduction of the data. Diff

44、raction gratings have uniform dispersion and give rise to higher orders. Higher orders shall be eliminated. For example, use of a filter eliminat-ing all wavelengths shorter than 370 nm yields a “clean” spectrum from 370 nm to 740 nm and this range serves most purposes for colorimetry of light sourc

45、es.4.1.2 Wavelength calibration It is recommended that the expanded uncertainty of the wavelength calibration should be 0.1 nm (k=2). The expanded uncertainty of the wavelength scale shall be less than 0.5 nm (k=2). The wavelength scale should be calibrated periodically. To satisfy these requirement

46、s, it is usually necessary that the ambient temperature be controlled within 1C. The wavelength scale can be calibrated by measuring the emission lines of known wavelengths from low-pressure mercury lamps (253.7 nm, 365.0 nm, 404.7 nm, 435.8nm, 546.1 nm) and neon discharge lamps (614.3 nm, 650.6 nm,

47、 703.2 nm). For grating type or prism-grating type monochromators, the wavelength scale can be checked at a few points since the scale is normally linear. For prism monochromators, the scale should be checked at several points and inter-polated over the entire wavelength region since the wavelength

48、scale is non-linear. 4.1.3 Bandwidth The choice of bandwidth depends on the purpose of measurement. For colo-rimetry of discharge lamps that can contain emission lines and/or narrow band emissions, the bandwidth shall be 2 nm or less and wavelength interval shall be integer multiples of the bandwidt

49、h. It should be noted, however, that the detector signal will be smaller as the bandwidth becomes narrower. For dis-charge lamps, the ratio of signal by emission lines to that by the continuum will be larger as the bandwidth becomes narrower. For grating type monochroma-tors, the bandwidth can be set by the entrance slit width and the exit slit width. The bandwidth can be measured and adjusted with the method shown in Section 4.1.4 Slit Scattering Function. For prism 3IES LM-58-13type monochromators, since the bandwidth varies with wavelength, it is difficult to match the wa