BS ISO 9211-1:2024
Optics and photonics. Optical coatings - Vocabulary

Standard No.

BS ISO 9211-1:2024

Release Date

2024

Published By

British Standards Institution (BSI)  GB  /  BSI

Latest

BS ISO 9211-1:2024

Introduction

Analysis of the core content of the standard

BS ISO 9211-1:2024, as the basic terminology standard in the field of optical coatings, has established a complete definition system covering the surface treatment technology of optical components. Compared with the 2018 version, the latest version mainly adds:

• Explicit definition of spectral optical density (D(λ))
• Subscript annotation specifications for wavelength/wavenumber average values
• Explanation of the difference between wavelength domain and wavenumber domain calculations of transmittance/reflectance/absorbance

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Optical property parameter system

Parameter type	Symbol representation	Calculation formula	Measurement points
Spectral transmittance	τ(λ)	τ(λ)=10-D(λ)	It is necessary to distinguish between specular transmission and diffuse transmission
Wavelength-averaged transmittance	τave(λ1→λ2)	1/(λ2-λ1)∫τ(λ)dλ	Systematically different from the wavenumber average
Optical density	D(λ)	lg(1/τ(λ))	New standardized definitions

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Coating function classification system

The standard divides coatings into 10 categories according to their main functions. Typical applications include:

• Reflection function (RE): The laser resonator lens must meet the HR (high reflection) characteristics
• Filtering function (FI): The Raman spectrometer uses FI-BR type band-stop filter
• Phase control (PC): The wave plate coating can achieve λ/4 phase delay

It is worth noting that composite function devices such as dichroic mirrors need to be marked with SC (splitting) and LP/SP (long/short pass) logos at the same time.

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Classification Atlas of Coating Defects

The standard systematically defines four types of defect morphology for the first time:

1. Point defects: including pinholes (≤50μm), splashes, etc.
2. Line defects: scratches to distinguish between ordinary type and hairline type (≤3μm)
3. Surface defects: optical uniformity problems such as haze and discoloration
4. Volume defects: interface failures such as blistering and peeling

The accompanying ISO 14997 provides standards for defect detection methods.

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Implementation Suggestions

Note for engineering applications:

• Witness samples should be processed in the same batch as actual components
• Polarization state (S/P component) must be marked when used at non-zero incident angles
• Wide spectrum applications must clearly use wavelength averaging or wavenumber averaging algorithms

BS ISO 9211-1:2024 Referenced Document

• ISO 11145 Optics and photonics — Lasers and laser-related equipment — Vocabulary and symbols
• ISO 80000-7 Grandeur and Units — Part 7: Light and Radiations — Amendment 1

BS ISO 9211-1:2024 history

• 2024 BS ISO 9211-1:2024 Optics and photonics. Optical coatings - Vocabulary
• 2020 BS ISO 9211-1:2018 Optics and photonics. Optical coatings. Vocabulary
• 2010 BS ISO 9211-1:2010 Optics and photonics - Optical coatings - Definitions
• 1995 BS ISO 9211-1:1994 Optics and optical instruments. Optical coatings-Definitions

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