What is ISO 21395‑1 - Test method for the refractive index of optical glasses about?
The refractive index of optical glasses has been measured by various methods, but until now, an International Standard for the measurement has not been available.
ISO 21395‑1 specifies the measuring method for the refractive index of optical glasses with the accuracy within 1 × 10−5 used in the spectral range from 365 nm to 2 400 nm.
The refractive index at an arbitrary wavelength can be calculated with the wavelength dispersion formula. The relative refractive index of optical glass is dependent on temperature, humidity, and atmospheric pressure too. The test method takes environment conditions, specimens prism, measuring apparatus, etc. for testing the refractive index of optical glasses.
NOTE: When measuring the refractive index with this method, it is necessary to consider temperature, pressure, humidity, and measurement errors. Expressions for the relations of these errors are described in ISO 17328.
Who is ISO 21395‑1 - Test method for the refractive index of optical glasses for?
ISO 21395‑1 on the test methods for the refractive index of optical glasses is useful for:
- Opticians
- Optical practitioners
- Optical instruments manufacturers
- Optical equipment’s purchasers
Why should you use ISO 21395‑1:2020 - Test method for the refractive index of optical glasses?
The refractive index of optical glasses is the most important characteristic for the optical elements to be manufactured from them. ISO 21395‑1 defines a suitable method for measuring the refractive index of optical glasses accurately and helps to improve communication between raw optical glass suppliers and optical element manufacturers.
The test results provide information about the method used, melt number, atmospheric pressure, humidity temperature, etc.
