New UV adhesives improve holographic films in AR 15 April 2022

DELO has developed DELO PHOTOBOND UV acrylates for optoelectronics that enable fast and true colour bonding of holographic films – manufactured by Covestro.

Augmented Reality Head-Up Displays (AR-HUDs) represent one of the most important future applications for holographic films, such as Bayfol® HX from Covestro. As these films are integrated into the windshield of vehicles, projections merge with reality so the navigation appears to be displayed directly on the road. The films allow for brighter and larger images while reducing installation space.

This holographic film technology also offers design freedom and reduced space requirements in the rear lights of cars and other automotive lighting applications. Customised holograms, such as a warning message that says ‘Stop’ in the driver’s field of vision, can be designed to increase safety.

No matter the application, holographic films are thin, lightweight and completely invisible under so-called ‘off-bragg’ conditions – whenever the coupled light does not meet certain requirements, such as the correct wavelength. The films usually consist of RGB-sensitive photopolymers on a transparent carrier film and are embedded between two protective cover layers.

Low optical interaction, high strength

A precondition for high component quality is low optical interaction between adhesive and photopolymer. Because of this, the adhesives are chemically adapted in such a way that they do not shift the absorption into other wavelength ranges when they are combined with the photopolymer. Therefore, the adhesives must ensure colour fidelity under all conditions.

Until now, mainly silicones have been used to fix the film layers. Silicones are versatile and high performance materials, however, this is offset by lower strength, slower curing and, in some cases, strong outgassing. During curing, they emit particles to their surroundings. Due to the potential impact on adjacent manufacturing processes, many automotive suppliers are striving for silicone-free production. The DELO PHOTOBOND UV acrylates tested by DELO and Covestro, show a highly improved outgassing behaviour compared to silicones and reach full strength within seconds under UV light. 

Deputy Editor

Claire Aldridge Deputy Editor t: +44 (0) 1727 743 889


Having spent a decade in the fastener industry experiencing every facet – from steel mills, fastener manufacturers, wholesalers, distributors, as well as machinery builders and plating + coating companies, Claire has developed an in-depth knowledge of all things fasteners.

Alongside visiting numerous companies, exhibitions and conferences around the world, Claire has also interviewed high profile figures – focusing on key topics impacting the sector and making sure readers stay up to date with the latest developments within the industry.