DELO has developed a new adhesive for automotive lighting applications. Photobond OB4189 is resistant to yellowing and, with its high aspect ratio, is particularly suitable for bonding microlens arrays, such as those found in headlights and projection systems.

These days, light is considered among the most important elements of automotive design and differentiation. Microlens arrays are a key player in these developments. They project LED light, which sits behind a very short focal length, providing sharp images and individual geometries. These systems are increasingly being used as optics in headlights and projection systems due to their low required installation depth.

For increased efficiency, such microlenses are often made of optically pure polymers. The microlens arrays are then fixed to a housing. With a high viscosity of 75,000 millipascal-seconds, Photobond OB4189 enables a high enough aspect ratio for the bonding process. The adhesive thus retains its shape after dispensing and does not flow, which is important for bonding microlens arrays. It is also resistant to yellowing, as shown by life cycle simulations of 500 hours at 140 C.

The modified acrylate is solvent-free and developed for a temperature application range of -40 to 120 C. It has a compressive shear strength of 30 megapascals (MPa) on polycarbonate and 25 MPa on PMMA. It can be cured with UV light (with a wavelength 365 nanometers) and visible light (with a wavelength of 400 nanometers). The typical exposure time with visible light with a layer thickness of 100 microns is 5 seconds. This enables high-precision active alignment processes for optical components and low cycle times in automated production.

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DELO Adhesives