Anti-fogging precise optical scales and limbs (RASA)


Project no.: 01.2.2-LMT-K-718-03-0058
Project website:

Project description:

Encoders are widely used for measurements of the very small displacements, position and movement speed in metrology instruments, motion systems, and high precision machining tools ranging from digital calipers to coordinate measuring machines. Optical scales are the most accurate encoders. One of the problems related to an operation of the optical scales is fogging of the scale surface when operating near a dew point. Therefore signals of the encoder can be disturbed or even remain unregistered.

Magnetic encoders are less sensitive to environmental issues than optical scales. However, magnetic encoders are accurate. Therefore, new generation non-fogging optical scales are necessary for high accuracy measurements in a humid environment. This problem can be solved by applying special hydrophilic ant-fogging coatings. However, at present optical scales with anti-fogging surfaces are not produced. Antifogging coatings are used for different glass or plastic optical components. However, these anti-fogging coatings are not suitable for optical scales due to the inferior mechanical properties.

Diamond like carbon (DLC) films can be used to solve this problem. DLC films are very hard, wear and corrosion resistance, optically transparent. Their properties can be changed in a broad range. An alternative approach is the application of a specially nanotextured superhydrophilic surface. To maximize surface wettability, superhydrophilic surface nanotexturing and deposition of DLC film can be combined. The fabricated film and/or nanotexture should protect the optical scale surface from dew without impairing or even improving the mechanical and optical properties of the scale; furthermore, the scale shall be resistant to the cleaning procedures.

Therefore, the aim of the project is the creation of the non-fogging optical scales technology. The project objective is the formation and study of the diamond-like carbon films, nano-textured surfaces as well as their combinations on glass and chromium substrates to create the non-fogging glass scales technology.

Project funding:

This research project is funded by the European Regional Development Fund according to the 2014–2020 Operational Programme for the European Union Funds’ Investments, under measure’s No. 01.2.2-LMT-K-718 activity “Research Projects Implemented by World-class Researcher Groups to develop R&D activities relevant to economic sectors, which could later be commercialized”.

Project results:

We plan to create the non-fogging optical scales technology, using diamond-like carbon films, nano-textured surfaces, and their combinations.

Period of project implementation: 2020-09-22 - 2023-09-01

Project coordinator: Kaunas University of Technology

Šarūnas Meškinis

2020 - 2023

Institute of Materials Science, Research Laboratory of Vacuum and Plasma Processes