DELO Launches New Adhesive for Automotive Lighting
DELO has developed a new adhesive for automotive lighting applications. DELO PHOTOBOND OB4189 is resistant to yellowing and, with its high aspect ratio, is particularly well-suited for securely bonding microlens arrays, such as those found in headlights and projection systems.
These days, light is regarded as one of the most crucial elements of automotive design and differentiation Microlens arrays play a pivotal role in driving these advancements. They project LED light, which sits behind a very short focal length, providing sharp images and individual geometries. These systems are increasingly being utilized 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, in other words, adhesives. The microlens arrays are then fixed to a housing. With a high viscosity of 75,000 mPa·s, DELO 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.
[caption id="attachment_156143" align="aligncenter" width="600"]
Automotive projection system schematic, adhesive shown in magenta for illustrative purposes (Figure: DELO).[/caption]
It also exhibits exceptional resistance to yellowing, as demonstrated through life cycle simulations of 500 hours at 140 °C. This attribute is crucial for applications that require high optical precision.
"With DELO PHOTOBOND OB4189, we added a high-viscosity and extremely yellowing-resistant product to our portfolio of temperature and humidity-resistant active alignment adhesives that is precisely tailored to the requirements of microlens arrays," commented Christoph Appel, Product Manager – LED (Automotive) at DELO.
The modified acrylate is solvent-free and developed for a temperature application range of -40 °C to +120 °C. It has a compressive shear strength of 30 MPa on polycarbonate and 25 MPa on PMMA. It can be cured with UV light (365 nm) and visible light (400 nm). The typical exposure time at 400 nm with a layer thickness of 100 μm is 5 seconds. This enables high-precision active alignment processes for optical components and low cycle times in automated production.
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