ISO 17861:2014

Fine ceramics (advanced ceramics, advanced technical ceramics) - Measurement method of spectral transmittance of fine ceramics thin films under humid condition

ISO 17861:2014 specifies a measurement method of spectral transmittance of fine ceramics thin films under humid condition. It provides test methods that will easily and accurately evaluate changes in optical properties of fine ceramic coatings in a humid atmosphere due to water adsorption.

Céramiques techniques — Méthode de mesurage de la transmittance spectrale des films minces de céramiques fines en conditions humides

General Information

• Status: Published
• Publication Date: 20-May-2014
• ICS: 81.060.30 - Advanced ceramics
• Technical Committee: ISO/TC 206 - Fine ceramics
• Drafting Committee: ISO/TC 206/WG 10 - Coatings
• Current Stage: 9020 - International Standard under periodical review
• Start Date: 15-Oct-2025
• Completion Date: 15-Oct-2025

Overview

ISO 17861:2014 defines a standardized measurement method for spectral transmittance of fine ceramics (advanced technical ceramics) thin films under humid conditions. The standard targets optical property changes caused by water adsorption in porous or columnar ceramic coatings. It prescribes environmental control, instrumentation, calibration and measurement sequences to compare transmittance in vacuum, low-humidity and high-humidity atmospheres.

Key topics and technical requirements

• Scope: Measurement of spectral transmittance of thin ceramic films deposited on transparent substrates (glass, polymer, etc.) to evaluate humidity-induced optical changes.
• Instrumentation: Recommended a double-beam spectrophotometer (integrating-sphere preferred) with desirable range ~300–2 500 nm; wavelength accuracy typically ±0.2 nm (UV‑visible) and ±1.0 nm (NIR); high repeatability at 0.1–0.5 nm.
• Environmental mini-chamber: Airtight chamber with quartz windows, valves and ports to permit measurements in vacuum, low-humidity and high-humidity without removing the sample. Leak testing and vacuum integrity are required.
• Vacuum and humidity control: Vacuum evacuation to <~40 Pa (pump speed >1.0 l/s recommended); temperature/humidity chamber set at 23 °C ±2 °C with test RH points typically 40 % ±2 % (low) and 80 % ±2 % (high). Heating of the mini-chamber during evacuation (up to 130 °C) is allowed to reduce residual water, but cooling to room temperature is required before measurement.
• Measurement procedure: Defined wavelength interval (e.g., 0.2 nm), scan speeds (different settings for <850 nm and >850 nm), baseline correction and spectrometer calibration (wavelength standards such as didymium/holmium oxide, polystyrene for IR).
• Data evaluation & reporting: Compare spectra across environments, calculate shifts (e.g., half-transmittance wavelength), and report instrument settings, environmental conditions, and sample description.

Applications and users

ISO 17861 is practical for organizations that develop, test or specify optical ceramic coatings where humidity stability matters:

• Manufacturers of anti-reflective coatings, IR/X-ray sensor filters, and optical band-pass filters for medical diagnostics.
• Quality assurance and R&D labs evaluating humidity-induced refractive index or transmittance shifts in porous/columnar thin films.
• Test labs requiring reproducible, comparable transmittance data for product specifications, failure analysis or material selection.

Related standards

• ISO 9211-1 (Optics and photonics - Optical coatings - Definitions)
• ISO 8980-3 (Ophthalmic optics - Transmittance specifications and test methods)

Keywords: ISO 17861, fine ceramics, spectral transmittance, thin films, humidity testing, environmental mini-chamber, spectrophotometer, water adsorption, optical coatings.

Standards Content (Sample)

INTERNATIONAL ISO
STANDARD 17861
First edition
2014-06-01
Fine ceramics (advanced ceramics,
advanced technical ceramics) —
Measurement method of spectral
transmittance of fine ceramics thin
films under humid condition
Céramiques techniques — Méthode de mesurage de la transmittance
spectrale des films minces de céramiques fines en conditions humides
Reference number
©
ISO 2014
© ISO 2014
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ii © ISO 2014 – All rights reserved

Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Principle . 2
5 Ambient room environment . 2
6 Test piece . 2
7 Measuring apparatus . 3
7.1 Apparatus configuration . 3
7.2 Spectrometer calibration . 4
8 Environmental conditions and control procedures . 4
9 Optical transmittance measurement procedure. 4
10 Evaluations of measured spectra . 5
11 Test report . 8
Annex A (informative) Structure and function of mini-chamber . 9
Foreword
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The committee responsible for this document is ISO/TC 206, Fine ceramics.
iv © ISO 2014 – All rights reserved

Introduction
Fine ceramics thin films are used in many applications such as anti-reflective coatings, infrared sensor
cut filters, X-ray sensor cut filters, and band-pass filters for medical analysis equipment. Even though
spectral transmittance of fine ceramics thin films are specified for each product, the refractive index
and optical property change when water vapor or other vapor is adsorbed to the surface of fine ceramics
thin films, because, generally, fine ceramics thin films have a columnar and voided structure. For this
matter, an International Standard that could evaluate the reliability under a range of humidity was
required. This International Standard provides test methods that will easily and accurately evaluate
effects of humidity on optical properties of fine ceramic coatings. By establishing this International
Standard, it aims for a rapid spread of this test method that will then lead to further growth of the
industry.
INTERNATIONAL STANDARD ISO 17861:2014(E)
Fine ceramics (advanced ceramics, advanced technical
ceramics) — Measurement method of spectral
transmittance of fine ceramics thin films under humid
condition
1 Scope
This International Standard specifies a measurement method of spectral transmittance of fine ceramics
thin films under humid condition. This International Standard provides test methods that will easily
and accurately evaluate changes in optical properties of fine ceramic coatings in a humid atmosphere
due to water adsorption.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and are
indispensable for its application. For dated references, only the edition cited applies. For undated
references, the latest edition of the referenced document (including any amendments) applies.
ISO 9211-1, Optics and photonics — Optical coatings — Definitions
ISO 8980-3:2013, Ophthalmic optics — Uncut finished spectacle lenses — Part 3: Transmittance specifications
and test methods
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 8980-3 and ISO 9211-1, and
the following apply.
3.1
half transmittance wavelength
λ
T1/2
center of a segment delimited by the wavelengths at which the transmittance is maximal and minimal
in a given wavelength range
3.2
environmental mini-chamber
small chamber to keep the environmental condition of a test piece contained inside the chamber
Note 1 to entry: The chamber is equipped with optical feed-through ports with a ball valve for evacuation or air-
circulation. The chamber shall be air-tight to keep the chamber in vacuum or with the atmosphere at a certain
humidity by closing the ball valves after evacuation or air-circulating to expose the test piece inside to a certain
atmosphere.
3.3
transmittance
fraction of intensity of incident optical beam transferring through the sample
3.4
monochromator
optical device that selects light beam with a certain wavelength with a range
3.5
spectrophotometer
optical instrument that measures spectral transmittance or reflectance
Note 1 to entry: The instrument consists of optical source, monochromator, sample chamber, optical detector,
signal processor, data processor, and interface.
3.6
double beam spectrophotometer
type of spectrophotometer that is utilized to compare the light intensity between the reference sample
and the test pieces
Note 1 to entry: Compared to single-beam spectrophotometer measures, a high stability of measurements is
obtained. The instrument consists of optics that divide a source light beam into two beams and two detectors.
The instability of a source beam mainly due to that of the source lamp is compensated by that of a reference beam.
3.7
integrating-sphere
optical component consisting of a hollow spherical cavity with its inner surface covered with a diffuse
white reflective coating
Note 1 to entry: The cavity is equipped with small holes to set a sample piece and for inlet and outlet of the light
beam.
4 Principle
Fine ceramics thin films sometimes possess a voided micro columnar structure, depending on film
deposition conditions. If a fine ceramics thin film with a voided structure is exposed to a certain
atmosphere with humidity, moisture in the atmosphere adsorbs on surfaces of the columns consisting
the voided structures. The quantity of adsorbed water is affected by hydrostatic vapor pressure in the
atmosphere. Depending on the quantity of water adsorbed, the refractive index of thin films changes,
resulting in the change in transmittance and reflectance. To evaluate effects of water adsorption on
to surface of voids of fine ceramics films on film optical properties, it is necessary to measure optical
properties under a certain atmosphere, typically in an atmosphere with a high humidity. In addition to
the measurements under a high humidity, for the sake of comparison, it is also necessary to measure the
properties in vacuum, i.e. under the condition without water adsorption and low humidity. By comparing
optical transmittance measured in vacuum, low humidity, and high humidity conditions, the stability of
fine ceramics thin films shall be evaluated.
5 Ambient room environment
The test shall be carried out under an ambient laboratory room atmosphere where deviations in
the temperature and humidity are small. In particular, to prevent the condensation of water in the
environmental mini-chamber, after removing the mini-chamber from the humidity-temperature
control chamber to the laboratory room, the ambient temperature should be controlled to a certain
range. Recommended laboratory room conditions are the following:
a) temperature: 23 °C ± 2 °C;
b) relative humidity: below 70 %.
NOTE Attention is needed to dew condensation when environmen
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