5740 International Standard (Iso INTE RNATIONAL ORGANIZATION FOR STANDARDIZATION MEXAYHAPOAHAR OPTAHW3ALWH HO CTAHAAPTW3AUWMORGANISATION INTERNATIONALE DE NO RMALISATION Road vehicles Rear view mirrors - Test method.for determining reflectance Vehicules routiers - Retroviseurs -- Methode d'essai pour la determination du facteur de reflexion Second edition - 1982-02-15 UDC 629.11.018.1 : 535.346.1 Ref. No. ISO 5740-1982 (E) iO 5740-1982 (E) Descriptors : road vehicles, driving mirrors, optical tests, reflectance. Price based on 4 pages Copyright International Organization for Standardization ed without license from IHS Not for Resale Foreword national standards institutes (Iso member bodies). The work of developing Inter- national Standards is carried out through IsO technical committees. Every member body interested in a subject for which a technical committee has been set up 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. Draft International Standards adopted by the technical committees are circulated to the merriber bodies for approval before their acceptance as International Standards by the Iso;Council. International Standard ISO 5740 was developed by Technical Committee ISO/TC 22, Road vehicles, and was circulated to the member bodies in November 1980. Austria Italy South Africa, Rep. of Belgium Japan Spain Brazil Korea, Dem. P. Rep. of Sweden Korea, Rep. of China Switzerland Egypt, Arab Rep. of Netherlands United Kingdom New Zealand France USSR Germany, F.R. Poland Iran Romania No member body expressed disapproval of the document. This second edition cancels and replaces the first edition (i.e. Is0 5740-1978). @ International Organization for Standardization, 1982 Printed in Switzerland without license from IHS Not for Resale ISO 5740-1982 (E) INTERNATIONAL STANDARD Road vehicles - Rear view mirrors - Test method for determining reflectance the values of -y (a) are identical with the spectral luminous efficiencies 1 Scope and field of application V(a). (See annex.) This International Standard specifies a test method for deter- 3.5 photopic vision [as defined in 45.25.055 of IEC Publi- mining the reflectance of rear view mirrors for road vehicles. cation 50(45) : Vision by the normal eye when it is adapted to levels of luminance of at least several candelas per square It applies to flat and convex surface mirrors intended for in- ternal and external mounting. metre. NOTE - The cone receptors of the retina are considered to be the prin- 2 References cipal active elements under these conditions and the spectrum appears coloured. IECPublication50(45), International Electrotechnical Vocabulary, Group 45 : Lighting. 3.6 reflectance : The ratio of reflected luminous flux to the incident iuminous flux (o). CIE Publication No 17 (1970), International lighting vocabulary -- Vol. 1 (published by the Central Office of the In- NOTE -- Where mixed reflectance occurs the total reflectance may be divided into two parts, regular reflectance (or) and diffused reflectance ternational Commission on Illumination). (od), hence the equation g = gr + Qd. NOTE -- The texts of the above are identical. 4 Apparatus 3 Definitions 4.1 General 3.1 CIE standard illuminant A [as defined in 45.15.145 of IEC Publication 50(45) : (Colorimetric illuminant), represent- The apparatus shall consist of a light source, a holder for the ing the ful radiator at T68 = 2 855,6 K. test sample, a reflectometer with a photodetector and an indicating meter (see figure 1), and means for eliminating the 3.2 CIE standard source A [as defined in 45.15.150 of IEC effects of extraneous light. Publication 50(45)] :Gas fllied tungsten filament lamp acorrelatedcolour operating at temperature The reflectometer in figure 1 measures the regular component T68 = 2 855,6 K. of refiectance. 3.3 CIE 1931 standard colorimetric observer [as defined The reflectometer may