ISO 23738:2021 pdf free download – Fine ceramics (advanced ceramics, advanced technical ceramics)一 Measurement method of spectral reflectance of fine ceramic thin films under humid conditions.
Fine ceramic thin films are used in many optical applications, such as anti-reflective coatings, infrared sensor cut filters, X-ray sensor cut filters and band-pass filters. Even though the spectral reflectance of fine ceramic thin films is specified for each product, the refractive index and the optical properties change if these thin films are exposed to a humid environment. The reason for such changes in the optical properties is that water is adsorbed onto the surfaces inside the voids of fine ceramic thin films. A standard for evaluating the reliability of these films under a range of humidity conditions is therefore necessary. A standard for determining the spectral transmittance under humid and dry conditions was developed in Iso 17861. This document provides test methods that enable changes in the spectral reflectance of fine ceramic coatings in a humid environment due to water adsorption to be evaluated easily and accurately. The aim of this document is to promote the rapid adoption of this test method to facilitate further growth in this industry.
11 Test report
The test report shall include the following:
a) Reference to this document (i.e. determined in accordance with Iso 23738).
b) Test date, name of the testing establishment, temperature and relative humidity.
c) Description of the test piece and its identity.
d) Description of the measuring apparatus.
e) Description of the test conditions, the vacuum evacuation time, the temperature and relative humidity of the temperature/humidity-controlled chamber, and the exposure time for the high- and low-humidity environments. In addition, the duration of time since the evacuation was finished or since the test piece was withdrawn from the temperature/humidity-controlled chamber.
fJ Description of measured data. In addition, if an optical glass filter is used for the wavelength calibration, the manufacturer and type as well as the distribution curve and reflectance value of the spectral reflectance. The spectral reflectance of the test pieces that was obtained under a vacuum, a high-humidity environment and a low-humidity environment. Any property shift data obtained under a vacuum, a high-humidity environment and a low-humidity environment.
A.1 Structure
Figure A.1 is a blueprint of an environmental mini-chamber. The environmental mini-chamber components comprise a sample guide and stage set, an optical feedthrough, a backside glass window and two ball valves for environmental control.
A.2 Function
A test piece shall be fixed tightly to the sample holder of the environmental mini-chamber by using wave-washers. Vacuum evacuation and the introduction of air with a regulated humidity shall be conducted by opening and closing the two ball valves.
A.3 Required performance
— No changes in pressure or humidity (absolute humidity) shall occur when both of the ball valves are closed.
— The glass plate of the optical-inlet feedthrough shall be fixed at a 5° tilt in relation to the normal direction of the test piece to prevent optical interference due to the glass plate.