Something i found quite useful about touch panels and i would like to share with the NXP community. Designing a touch sensor is not an easy task. The touch sensor front panel you choose is more important than you think.
In touch sensor design there is a high level of complexity and many design choices to consider. Complex physical phenomena and cost decisions also play their part. So, as it always happens in engineering design, engineers make compromises in each step of the way. Compromises also happen on the touch sensor front panel material.
The amount of design choices a touch sensor designer has to make is overwhelming. Each design choice targets to fulfil the requirements of the customer, but they impact conflicting parts of the design.
Let’s assume that all the design aspects of the touch sensor are defined, apart from the cover glass selection. The touch sensor front panel is usually made of glass, hence the term “cover glass”.
This article addresses:
- The steps during which the cover glass selection is under consideration.
- The differences between different cover glasses.
- The methods touch sensor designers use in order to achieve the most efficient design.
- Finally, we will see a real-life example. Based on simulation data, we will examine how different cover glass thicknesses and glass permittivities affect the sensitivity of a touch sensor.
We start with the bigger picture, how the whole touch sensor is designed and then, narrow it down to the cover glass selection.