Non-destructive tests for optical bondings

In the case of incorrect UV bonding, local wetting can deteriorate over the course of (application) time — and result in undesirable, clearly visible, and thus disturbing artifacts. The non-destructive analysis makes this clear. (Image: Wammes+&+Partner+GmbH)

Wammes and Partner are developing a new method to test the quality of UV-cured optical bondings without destroying them. The examination of the optical bonding quality immediately after the bonding process offers the opportunity to quickly identify problems and make adjustments if necessary.

This is made possible through the use of the so-called Pattern-Approach, which is supported by powerful mathematical algorithms. Because: The specialized analysis of the measurement of optically clear structures inherently results in a poor signal-to-noise ratio. With such noisy signals, it is very difficult to evaluate a signal based on its amplitude and to find a stable pattern. The Pattern-Approach provides very understandable RAW data, from which relevant information can be filtered out of the noise through powerful computing.

The non-destructive analysis focuses strictly on the adhesive layer and the boundary surfaces, providing a wide range of high-resolution details, both for microscopic and macroscopic applications. The very high reliability of the results has been proven so far in more than 2,000 different field cases. Additionally, the new analysis can be used for many other bonding problems beyond UV resin-based adhesives.

"A subsequent analysis of the quality of the optical bonding of a given display was so far quite pointless, as it was either of little informative value or, upon closer inspection, destroyed the display. With our new method, semi-finished products and devices can now be analyzed for their bonding without destroying, delaminating, or impairing the integrated display," explains Klaus Wammes, Managing Director of Wammes and Partner GmbH.