ISO 21395-2 pdf download Optics and photonics — Test method for refractive index of optical glasses — Part 2: V-block refractometer method
This document specifies a method to determine the refractive index of optical glass with the accuracywithin 3 × 10-5 at the wavelength range from 365 nm to 2 400 nm by using the V-block refractometermethod.
While this document can be used for non-glass materials, the user is informed that only optical glasshas been considered in the development of this document, and other materials can have issues, whichhave not been taken into consideration.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their contentconstitutes requirements of this document. For dated references, only the edition cited applies.Forundated references, the latest edition of the referenced document (including any amendments) applies.ISo 280,Essential oils — Determination of refractive index
ISO 9802,Raw optical glass — Vocabulary
ISO 21395-1,0ptics and photonics —Test method for refractive index of optical glasses—Part 1:Minimumdeviation method
ISO 80000-1,Quantities and units — Part 1: General
ISo 80000-3,Quantities and units — Part 3: Space and time
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 9802,ISo 80000-1,ISO 8000o-3 and the following apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:- ISo online browsing platform: available at https://www.iso.org/obp
-IEC Electropedia: available at https://www.electropedia.org/3.1
prism manufactured from optical glass material with a known refractive index3.2
refractive index matching liquid
transparent liquid having the refractive index close to that of the specimen
As shown in Figure 1 a), when a beam aligned perpendicular to the entrance face transmits throughthe V-block prism, it is refracted at the interface between the V-block prism and the specimen and exitsfrom the exit face nominally parallel to the entrance face. T’he relationship among the deviation angleof the emergent beam to the incident beam, y, the relative refractive index of the V-block prism to themeasurement atmosphere,N, and the relative refractive index of the specimen to the measurementatmosphere,n, is expressed by the following Formula (1:
is the relative refractive index of the specimen to the measurement atmosphere;Nis the relative refractive index of the v-block prism to the measurement atmosphere;
is the deviation angle.
NOTE In general, the symbol of the refractive index is the lowercase n.However, this document intentionallyuses the capital letter N for the relative refractive index of the V-block prism to make it more distinct from that ofthe specimen.
The sign of the deviation angle of the emergent beam shall be positive (+) for upward deviation (that is,n >N) and negative (-) for downward deviation (n