Making the stack stick: bonding and DTCs
Like most things in life, displays change, evolve and, happily, improve. As classic displays and control elements are increasingly being replaced by modern display stacks (Display Touch Cover lens or DTC), naturally new processes will come into play to bond the cover glasses or DTCs into their housings.
As the word ‘stack’ might suggest, various parts of these displays are bonded together. Firstly, the cover glass is bonded over its entire surface with a touch sensor using a transparent adhesive. The cover glass touch unit is then bonded to the display module using the same method.
Either a damping or structural adhesive can be used for the subsequent bonding of the display stack into a frame or housing. Of course, we must add a brief caveat here, as the overall process depends on several factors: the application area, material, DTC design and construction requirements. Because bonding a display stack isn’t always as straightforward as it might seem and there are plenty of considerations and challenges to be taken into account at every stage.
For example, the bonds must be resistant to moisture, grease, chemicals and UV rays. Then, additionally, each material expands and contracts at different rates and the chosen adhesive must be able to compensate for this. This means that judgements must be made in the early stages to decide which kind of bonding is the most appropriate. Simply – it’s all about the pros and cons.
| Double-sided tape bonding | |
|---|---|
| Pros | - ‘Easier’ bonding in the front frame - Fast further processing of the assembly (DTC + front frame) - Cost-effective solution |
| Cons | - Visible gap between front frame and cover glass - Dirt accumulation in the joint |
| Liquid Adhesive bonding | |
|---|---|
| Pros | - Gap between front frame and cover glass is filled, which contributes to better sealing - Achievable protection class IP6X - Ensures better stability between frame and DCT |
| Cons | - The liquid adhesive takes longer to harden than the tape - The further processing of the assembly takes longer - High effort when dosing and positioning the parts |
Our Avnet Displays come in a range of form-factors and our display-experts are on hand to guide you in the creation of display or touch solutions that meet your requirements. Find out how Avnet Displays can propel your product innovation and get in touch today.
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