1、December 2015 English price group 8No part of this translation may be reproduced without prior permission ofDIN Deutsches Institut fr Normung e. V., Berlin. Beuth Verlag GmbH, 10772 Berlin, Germany,has the exclusive right of sale for German Standards (DIN-Normen).ICS 37.020!%JwZ“2398455www.din.deDIN
2、 ISO 14490-6Optics and photonics Test methods for telescopic systems Part 6: Test methods for veiling glare index (ISO 14490-6:2014),English translation of DIN ISO 14490-6:2015-12Optik und Photonik Prfverfahren fr Fernrohre Teil 6: Bestimmung des Falschlichtanteils (ISO 14490-6:2014),Englische berse
3、tzung von DIN ISO 14490-6:2015-12Optique et photonique Mthodes dessai pour systmes tlescopiques Partie 6: Mthodes dessai de lindice de lumire parasite (ISO 14490-6:2014),Traduction anglaise de DIN ISO 14490-6:2015-12SupersedesDIN ISO 14490-6:2006-08www.beuth.deDocument comprises pagesDTranslation by
4、 DIN-Sprachendienst.In case of doubt, the German-language original shall be considered authoritative.1212.151 Scope .2 Normative references 3 Terms and definitions .4 General considerations 5 Principle 6 Test arrangement .6.1 General .6.2 Integrating sphere 6.3 Object-side collimator.6.4 Test specim
5、en mounting .6.5 Limiting stop .6.6 Measurement and evaluation unit .7 Procedure.7.1 Adjustment of the measurement set-up .7.2 Determination of results .8 Presentation of results .9 Repeatability 10 Test report .Annex A (informative) Method for determination of the luminance ratio of the black refer
6、ence surface to the internal surface of the integrating sphere .Bibliography A comma is used as the decimal marker. Contents Page National foreword. 3 National Annex NA (informative) Bibliography 4 2DIN ISO 14490-6:2015-12 5555666778888889991012National foreword This document (EN ISO 14490-6:2014) h
7、as been prepared by Technical Committee ISO/TC 172 “Optics and photonics”, Subcommittee SC 4 “Telescopic systems” (Secretariat: GOST R, Russia) with the active participation of German experts. The responsible German body involved in its preparation was DIN-Normenausschuss Feinmechanik und Optik (DIN
8、 Standards Committee Optics and Precision Mechanics), Working Committee NA 027-01-10 AA Fernrohre und Vergrerungsglser. ISO 14490-6 is part of an international standards series. The parts of this series that have been published or are intended to be published as German Standards are listed in the Na
9、tional Annex NA. Further standards dealing with telescopic systems are also listed in the National Annex NA. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. DIN shall not be held responsible for identifying any or all such patent
10、rights. The DIN Standard corresponding to the International Standard referred to in this document is as follows: ISO 14490-1 DIN ISO 14490-1 Amendments This standard differs from DIN ISO 14490-6:2006-08 as follows: a) ISO 14490-6:2014 has been adopted; b) for the achromatic lens for the object-side
11、collimator, a minimum f-number has been specified; c) the standard has been editorially revised. Previous editions DIN 58389-1: 1996-12, 1999-02 DIN ISO 14490-6: 2006-08 3DIN ISO 14490-6:2015-12 National Annex NA (informative) Bibliography DIN ISO 9336-3, Optics and optical instruments Optical trans
12、fer function Application Part 3: Telescopes DIN ISO 10109-4, Optics and optical instruments Environmental requirements Part 4: Test requirements for telescopic systems DIN ISO 14133-1, Optics and optical instruments Specifications for binoculars, monoculars and spotting scopes Part 1: General purpos
13、e instruments DIN ISO 14133-2, Optics and optical instruments Specifications for binoculars, monoculars and spotting scopes Part 2: High performance instruments DIN ISO 14135-1, Optics and photonics Specifications for telescopic sights Part 1: General purpose instruments DIN ISO 14135-2, Optics and
14、photonics Specifications for telescopic sights Part 2: High-performance instruments DIN ISO 14490-1, Optics and optical instruments Test methods for telescopic systems Part 1: Test methods for basic characteristics DIN ISO 14490-2, Optics and optical instruments Test methods for telescopic systems P
15、art 2: Test methods for binocular systems DIN ISO 14490-3, Optics and optical instruments Test methods for telescopic systems Part 3: Test methods for telescopic sights DIN ISO 14490-5, Optics and optical instruments Test methods for telescopic systems Part 5: Test methods for transmittance DIN ISO
16、14490-7, Optics and optical instruments Test methods for telescopic systems Part 7: Test methods for limit of resolution ISO 14132-1, Optics and optical instruments Vocabulary for telescopic systems Part 1: General terms and alphabetical indexes of terms in ISO 14132 ISO 14132-2, Optics and optical
17、instruments Vocabulary for telescopic systems Part 2: Terms for binoculars, monoculars and spotting scopes ISO 14132-3, Optics and optical instruments Vocabulary for telescopic systems Part 3: Terms for telescopic sights ISO 14132-4, Optics and optical instruments Vocabulary for telescopic systems P
18、art 4: Terms for astronomical telescopes 4DIN ISO 14490-6:2015-12 1 ScopeThis part of ISO 14490 specifies the test methods for the determination of the veiling glare index of telescopic systems and observational telescopic instruments.2 Normative referencesThe following documents, in whole or in par
19、t, are normatively referenced in this document and are indispensable for its application. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.ISO 9358:1994, Optics and optical instruments Veili
20、ng glare of image forming systems Definitions and methods of measurementISO 14132-1, Optics and photonics Vocabulary for telescopic systems Part 1: General terms and alphabetical indexes of terms in ISO 14132ISO 14490-1:2005, Optics and photonics Test methods for telescopic systems Part 1: Test meth
21、ods for basic characteristics3 Terms and definitionsFor the purposes of this document, the terms and definitions given in ISO 14132-1 apply.4 General considerationsThe veiling glare test methods are generally described in ISO 9358:1994. ISO 9358:1994 deals with arbitrary optical instruments and cont
22、ains two basic approaches to measuring the veiling glare, namely integral (or black patch) method and analytical (or glare spread function) method.For terrestrial telescopes with which this part of ISO 14490 deals, the black patch method is more adequate while the glare spread function might prove t
23、o be better for astronomical telescopes. For the moment, consideration in this part of ISO 14490 is given only to the black patch method. If need of measuring the glare spread function arises, the reference shall be made directly to appropriate clauses of ISO 9358:1994.From the classification given
24、in ISO 9358:1994, Clause 3, the case where both the object and the image are at infinity will usually apply to telescopic systems. Clauses 6 and 7 give detailed and more specific descriptions of the general test method given in ISO 9358:1994, 4.1 and of test conditions given in ISO 9358:1994, 5.1.Op
25、tics and photonics Test methods for telescopic systems Part 6: Test methods for veiling glare index 5DIN ISO 14490-6:2015-12 5 PrincipleThe determination of the veiling glare index, S, is based upon the measurement of the illuminance of the image of a black surface in diffuse scattered white light a
26、nd the measurement of the illuminance of the image of the white background.The veiling glare of an optical instrument is determined by the ratio of the illuminance, E1, of the image of a black surface within a white illuminated wide surface to the illuminance, E2, of an image of a totally white surf
27、ace.SEE=12(1)NOTE In both cases, the white surface ensures a homogenous distribution of the illumination across the whole entrance pupil of the test specimen.6 Test arrangement6.1 GeneralThe measurement set-up consists of an integrating sphere, an object-side collimator, the test specimen mounting,
28、the limiting stop, the image-side collimator, and the measurement and evaluation unit.See Figures 1 and 2.Key1 black object simulator 6 object-side collimator lens 11 filter2 selectable segments 7 slewing point I 12 image-side collimator lens3 integrating sphere 8 test specimen 13 measuring stop4 ba
29、ffle 9 slewing point II 14 radiation detector5 light source 10 limiting stop 15 indicatoraThe measurement and evaluation unit consists of the limiting stop, filter, image-side collimator lens, measuring stop, radiation detector, and indicator.Figure 1 Test arrangement for on-axis measurement (schema
30、tic)6DIN ISO 14490-6:2015-12 Key1 black object simulator 6 object-side collimator lens 11 filter2 selectable segments 7 slewing point I 12 image-side collimator lens3 integrating sphere 8 test specimen 13 measuring stop4 baffle 9 slewing point II 14 radiation detector5 light source 10 limiting stop
31、15 indicatoraThe measurement and evaluation unit consists of the limiting stop, filter, image-side collimator lens, measuring stop, radiation detector, and indicator.Figure 2 Test arrangement for off-axis measurement (schematic)6.2 Integrating sphereThe integrating sphere should have a diameter 15 t
32、imes the diameter of the entrance pupil of the test specimen, but at least 1 m.It has two opposite openings. In the first opening, the collimating lens is inserted. In the second opening, removable circular elements adapted to the interior surface of the sphere are inserted to act as white and black
33、 reference surfaces.The white reference surface is composed of a disk that entirely fills the second opening in the sphere. The black reference surface is composed of a disk with an aperture of the desired diameter (i.e. an annulus) that is fitted into the second opening in the sphere. It is followe
34、d by a light trap outside the sphere. The luminance of the light trap shall be less than 0,1 % of the luminance of the illuminated interior surface of the sphere.NOTE See Annex A for background information about the black patch method.The interior surface of the sphere and the annular and circular e
35、lements shall be white and opaque. The reflectance across the whole spectral range from 380 nm to 780 nm should be at least 85 %.The light source shall emit a constant radiant flux. The radiant flux shall not change more than 1 % during the measurement of one pair of values. The light source shall c
36、orrespond to a black body source with a colour temperature between 2 800 K and 3 200 K.6.3 Object-side collimatorFor the purpose of a collimator, an achromatic lens with a minimum f-number of 10 (i.e. maximum relative aperture 1:10) is appropriate, but the aperture shall exceed 1,2 times the diamete
37、r of the objective lens of the test specimen.The focal length of the collimator and the interior diameter of the sphere shall be identical. All glass-air surfaces need an antireflection coating.7DIN ISO 14490-6:2015-12 The object-side collimator is being fixed in the opening so that the collimator w
38、ith its frame closes the interior of the sphere and the lens is located outside the sphere.6.4 Test specimen mountingThe test specimen mounting shall be constructed in a way that the combination of the test specimen and the measurement and evaluation unit can be adjusted and held stable and turned a
39、round the entrance pupil for off-axis measurements.Additionally, the test specimen mounting shall be constructed in a way that the measurement and evaluation unit can be turned around the exit pupil for off-axis measurements.6.5 Limiting stopIn the plane of the test specimens exit pupil, a limiting
40、stop of 8 mm diameter shall be attached.NOTE 1 This limiting stop prevents light which would not reach the observers eye from entering the radiation detector.NOTE 2 A limiting stop of 8 mm diameter is assumed to match the eyes maximum pupil diameter.6.6 Measurement and evaluation unitThe measurement
41、 and evaluation unit consists of the limiting stop, the filter, the image-side collimator, the radiation detector, and the indicator.The image-side collimator (achromatic lens with antireflection coatings) images the white or black reference surface at the surface of the radiation detector.It shall
42、be positioned directly behind the test specimens exit pupil. The clear aperture shall be at least 10 mm.At the image surface in front of the radiation detector, a measuring stop with a diameter of 20 % to 50 % of the diameter of the image of the black surface is arranged.The filter serves to convert
43、 the spectral sensitivity curve of the detector to the photopic response curve of the human eye for the radiation source used.The size and aperture of the radiation detector shall be sufficient to collect all radiation which is transmitted by the measuring stop.7 Procedure7.1 Adjustment of the measu
44、rement set-upThoroughly clean the optical surfaces of the collimators and of the test specimen.The size of the black surface corresponds to a 1 object-side field of view; this is valid for test specimens with at least 2 field of view. If the test specimen has a smaller field of view, then the object
45、-side angle of the black surface should correspond to about half the test specimens field of view.Attach the test specimen as closely as possible to the object-side collimator and centre it to the optical axis. This ensures that the light enters the test specimen with the maximum solid angle.7.2 Det
46、ermination of resultsFirst, measure the illuminance in the image of the white surface, then measure the illuminance in the image of the black surface.8DIN ISO 14490-6:2015-12 For the determination of the veiling glare index of off-axis object points, slew the test specimen around the entrance pupil
47、and slew the measurement and evaluation unit around the exit pupil.For the measurement off-axis, object points of 0,5 and 0,7 of half the field of view shall be chosen.Because the veiling glare index of non-rotationally-symmetric erecting systems (prisms) is not equal at corresponding azimuths, dete
48、rmine the maximum value.8 Presentation of resultsThe veiling glare index, S, is expressed as a percentage.The measurement results shall be presented in tabular and in graphical form, as follows.a) In the presentation in tabular form, the measurements, and the calculated values of the veiling glare i
49、ndex (see Note) shall be given; the values shall be expressed as a percentage to one decimal digit.b) In the graphical presentation, the values of the veiling glare index shall be plotted over the angles of the field of view.NOTE The measurement of the veiling glare index depends on the measurement environment, which is determined in detail by the black surface, the diameter of the limiting stop at the test specimens exit pupil, and the collimating lens.9 RepeatabilityThe relativ
