1、BRITISH STANDARD BS ISO 15368:2001 Optics and optical instruments Measurement of reflectance of plane surfaces and transmittance of plane parallel elements ICS 17.180.01; 37.020 NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBS ISO 15368:2001 This British Standard, having been
2、 prepared under the direction of the Consumer Products and Services Sector Policy and Strategy Committee, was published under the authority of the Standards Policy and Strategy Committee and comes into effect on 26 September 2001 BSI 26 September-2001 ISBN 0 580 38490 X National foreword This Britis
3、h Standard reproduces verbatim ISO 15368:2001 and implements it as the UK national standard. The UK participation in its preparation was entrusted to Technical Committee CPW/172, Optics and optical instruments, which has the responsibility to: A list of organizations represented on this committee ca
4、n be obtained on request to its secretary. Cross-references The British Standards which implement international or European publications referred to in this document may be found in the BSI Standards Catalogue under the section entitled “International Standards Correspondence Index”, or by using the
5、 “Find” facility of the BSI Standards Electronic Catalogue. A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are responsible for their correct application. Compliance with a British Standard does not of itself confer immunity from
6、legal obligations. aid enquirers to understand the text; present to the responsible international/European committee any enquiries on the interpretation, or proposals for change, and keep the UK interests informed; monitor related international and European developments and promulgate them in the UK
7、. Summary of pages This document comprises a front cover, an inside front cover, the ISO title page, pages ii to v, a blank page, pages 1 to 13 and a back cover. The BSI copyright date displayed in this document indicates when the document was last issued. Amendments issued since publication Amd. No
8、. Date CommentsINTERNATIONAL STANDARD ISO 15368 First edition 2001-08-01 Reference number ISO 15368:2001(E) OSI 2001 Optics and optical instruments Measurement of reflectance of plane surfaces and transmittance of plane parallel elements Optique et instruments doptique Mthode de mesurage de la rflec
9、tance des surfaces planes et de la transmittance des lments plan parallleISO 15368:2001(E) iiISO 15368:2001(E) ISO 1002 All rithgs rreseved iii Contents Page 1 Scope . 1 2 Normative references . 1 3 Terms and definitions 2 4 Symbols and units 2 5 Test specimen . 2 6 Measuring apparatus 3 7 Test cond
10、itions 4 8 Test procedure 5 9 Main error factors . 7 10 Test report 9 Annexes A Spectrophotometers 10 A.1 General . 10 A.2 Dispersion type spectrophotometer 10 A.3 Fourier-transform type spectrometer . 11 B Refractive index of synthetic fused silica 12 Bibliography. 13ISO 15368:2001(E) iv ISO 1002 A
11、ll rithgs rreseved Foreword ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standards is normally carried out through ISO technical committees. Each member body interested in a su
12、bject for which a technical committee has been established has the right to be represented on that committee. International organizations, governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical Commission (
13、IEC) on all matters of electrotechnical standardization. International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 3. Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an Inter
14、national Standard requires approval by at least 75 % of the member bodies casting a vote. Attention is drawn to the possibility that some of the elements of this International Standard may be the subject of patent rights. ISO shall not be held responsible for identifying any or all such patent right
15、s. International Standard ISO 15368 was prepared by Technical Committee ISO/TC 172, Optics and optical instruments,S ub co m mi t te eSC1 ,Fundamental standards. Annexes A and B of this International Standard are for information only.ISO 15368:2001(E) ISO 1002 All rithgs rreseved v Introduction Meas
16、urements of reflectance and transmittance using spectrophotometers are the most fundamental methods for the characterization of optical components. Since the spectrophotometric methods are basic and normal, they are extensively used and further give measurement data for a wide range of wavelengths.
17、This International Standard describes the measurement of reflectance and transmittance using spectrophotometers which provides data with high reproducibility and repeatability.INTERNATIONAL STANDARD ISO 15368:2001(E) ISO 1002 All rithgs rreseved 1 Optics and optical instruments Measurement of reflec
18、tance of plane surfaces and transmittance of plane parallel elements 1 Scope This International Standard gives rules for the measurement of the spectral reflectance of plane surfaces and spectral transmittance of plane parallel elements using spectrophotometers over the spectral range to . The trans
19、mittance and the reflectance of optical components are generally divided into two parts as follows: (1) (2) where is the regular transmittance; is the diffuse transmittance; is the regular reflectance; is the diffuse reflectance. This International Standard applies only to measurements of the regula
20、r transmittance and the regular reflectance; it does not apply to those of the diffuse transmittance and the diffuse reflectance. This International Standard is applicable to test specimens which are coated or uncoated optical components without optical power. 2 Normative references The following no
21、rmative documents contain provisions which, through reference in this text, constitute provisions of this International Standard. For dated references, subsequent amendments to, or revisions of, any of these publications do not apply. However, parties to agreements based on this International Standa
22、rd are encouraged to investigate the possibility of applying the most recent editions of the normative documents indicated below. For undated references, the latest edition of the normative document referred to applies. Members of ISO and IEC maintain registers of currently valid International Stand
23、ards. IEC 60050-845:1987, International Electrotechnical Vocabulary Chapter 845: Lighting ISO 31-6:1992, Quantities and units Part 6: Light and related electromagnetic radiations ISO 9211-1:1994, Optics and optical instruments Optical coatings Part 1: Definitions ISO 9211-2:1994, Optics and optical
24、instruments Optical coatings Part 2: Optical properties ISO 10110-8:1997, Optics and optical instruments Preparation of drawings for optical elements and systems Part 8: Surface texture 190 nm 25 m = r + d = r + d r d r dISO 15368:2001(E) 2 ISO 1002 All rithgs rreseved 3 Terms and definitions For th
25、e purposes of this International Standard, the terms and definitions given in ISO 31-6, ISO 9211-1 and the following (which are given in IEC 60050-845) apply. 3.1 transmittance for incident radiation of given spectral composition, polarization and geometrical distribution ratio of the transmitted ra
26、diant or luminous flux to the incident flux in the given conditions 3.2 regular transmittance ratio of the regularly transmitted part of the whole transmitted flux to the incident flux 3.3 internal transmittance ratio of the radiation flux reaching the internal exit surface of the layer to the flux
27、that enters into the layer after crossing the entry surface 3.4 reflectance for incident radiation of given spectral composition, polarization and geometrical distribution ratio of the reflected radiant or luminous flux to the incident flux in the given conditions 3.5 regular reflectance specular re
28、flectance ratio of the regularly reflected part of the whole reflected flux to the incident flux 4 Symbols and units For the purposes of this International Standard, the following symbols and units apply. wavelength, expressed in nanometres angle of incidence, expressed in degrees p, s state of pola
29、rization transmittance regular transmittance internal transmittance reflectance regular reflectance 5T e s t s p e c i m e n Storage, cleaning and preparation of a test specimen shall be carried out in accordance with the instructions of the manufacturer on the test specimen for normal use. Waveleng
30、th, angle of incidence and state of polarization shall correspond to those specified by the manufacturer for the use of the test specimen. i r i rISO 15368:2001(E) ISO 1002 All rithgs rreseved 3 6 Measuring apparatus For the measurement specified in this International Standard, a spectrophotometer i
31、s required. Figure 1 shows an example of a double beam, dispersion type spectrophotometer. It consists of a light source, a monochromator, a specimen compartment, a detector unit and a control unit. Details of the apparatus are described in annex A. Key L Light source FF i l t e r b o x SS l i t D D
32、ispersive element M Monochromator SC Specimen compartment CO Collecting optics BB a f f l e PF Polarization filter CM Chopper mirror T Test beam R Reference beam DU Detector unit CU Control unit Figure 1 Standard arrangement of a spectrophotometerISO 15368:2001(E) 4 ISO 1002 All rithgs rreseved 7 Te
33、st conditions 7.1 General The light source, divergence of beam, beam diameter on the specimen, wavelength, spectral resolution, stepping interval, incident angle, detector and numerical correction shall be selected and documented. 7.2 Light source The temporal variation of the intensity of the light
34、 source shall be measured and documented. The state of polarization (p or s) of the beam shall be selected and documented. NOTE The state of polarization of the radiation reaching the detector may be affected by reflection on components in the reference/sample paths. It is suggested to rotate the sa
35、mple in its incidence plane to check for polarization effects. The beam diameter on the specimen shall be larger than . On the surface of the specimen the beam profile shall be smooth so that the local peak power density does not exceed the average power density by a factor of greater than two. The
36、beam diameter and the beam divergence (see also 9.9) shall be documented. 7.3 Monochromator The type of dispersive element and its characteristics shall be documented. Optics for blocking out higher order diffraction light shall be documented. The spectral range and spectral resolution shall be sele
37、cted in order to satisfy the specification of the measurement, and be documented. The type of spectrophotometer (single or double beam, dispersion or Fourier-transform) shall be documented. 7.4 Detection system An appropriate detector for the measuring spectral region shall be selected and documente
38、d. In the case of a dispersion type spectrophotometer, a lock-in detection technique is frequently used and a light chopper or a chopper mirror is installed in the beam to modulate the output signal. The detection system shall have a dynamic range greater than and a deviation from linearity less tha
39、n . Photometric linearity shall be calibrated by a double aperture method that uses double apertures and neutral density filters 1. When an integrating sphere or a diffuser is used, this shall be documented. 7.5 Numerical correction Numerical correction can include spectral correction, averaging, sm
40、oothing, calibration of photometric linearity and others. Spectral correction can be made referring to an appropriate wavelength standard (see 9.2). Random noise can be reduced by averaging or smoothing. Averaging can be made by repeating measurement or increasing sampling time. Smoothing can be mad
41、e by averaging data in the finite spectral bandwidth after measurement, although it reduces spectral resolution. Sampling time and smoothing factors shall be documented. For details on the calibration of photometric linearity, see 7.4. Calibration of the spectrophotometer can be done by measuring th
42、e transmittance of a reference sample (standard) using the method given in 8.2.1. A reference sample for the transmittance from ultraviolet to near infrared region shall be an accurately parallel plate of fused silica with P2 grade surface specified in ISO 10110-8. Accuracy and 1mm 10 4 10 2ISO 1536
43、8:2001(E) ISO 1002 All rithgs rreseved 5 repeatability of the transmittance of this reference sample is from to including photometric noise. Other standard reference materials which are checked at an accredited laboratory may be used. 8 Test procedure 8.1 Measurement of reflectance 8.1.1 General Eit
44、her of the two types of measurements of reflectance, a direct method or a relative method, shall be chosen. The incident angle shall be selected according to the manufacturers instruction. Reflectance of normal incidence cannot usually be measured and the incident angle from to instead of , which sh
45、all be documented, is used. In the case of an incident angle other than , the reflectance depends on the state of polarization of the incident light, so that in the case of an angle larger than , the state (p or s) shall also be selected and documented. 8.1.2 Direct measurement of regular reflectanc
46、e Figure 2 shows two methods of the direct measurement of reflectance. In Figure 2 a), the reflected flux without a specimen is measured, and then the reflected flux with the specimen is measured after changing the optical arrangement as in Figure 2 b) and c). The regular reflectance of the specimen
47、 is given as (3) in the case of an arrangement as shown in Figure 2 b) (4) in the case of an arrangement as shown in Figure 2 c) irrespective of the magnitudes of the reflectance of the reference mirror and other optics. 8.1.3 Relative measurement of regular reflectance The relative measurement is e
48、asier than the direct measurement. An example of a reference sample for the reflectance is an aluminum mirror or a fused silica plate with a wedge angle, polished smoothly and kept clean. The successive measurements of the reflected flux of the reference sample and that of a specimen are made using
49、the arrangement of Figure 2 a). Then the regular reflectance of the specimen is given as (5) where is the regular reflectance of the reference sample. The value is calibrated separately by the direct method given in 8.1.2. For a low reflectance specimen such as an anti-reflection coated or uncoated glass plate, the relative measurement is recommended. In such a case, fused silica plate is used as the reference sample for the region from ultraviolet to near infrared. The ref
