Innovative touch technology and materials
With the widespread use of touchscreens and their use in a wide variety of applications, there has also been a noticeable innovation in touch technologies and materials in recent years.
A recognizable trend is the increasing reduction in the strength of the sensor's substrates. While in 2009 the carrier material of the ITO Touch Sensor was still 0.5 mm, in 2012 the thickness was only 0.2 mm.
This significant reduction in the thickness of the carrier material is due to the introduction of PET film as the carrier material for the ITO Touch Sensor.
ITO coated PET (polyester) layers
Different techniques are available for the construction of capacitive touchscreens. One is the construction of lead wires or the application of transparent conductive materials such as indium tin oxide (ITO) to a sandwich film layer of polyester or a glass substrate.
When polyester is used, the electric field is created with the help of two grid-shaped, ITO-coated PET layers.
Light transmission and surface resistance are directly proportional to each other. The higher the resistance, the higher the light transmittance, which is due to the fact that the higher the desired light transmittance, the thinner the ITO layer typically is.
The sensor is attached directly to the surface using highly transparent adhesive. In this way, the controller can read out the touch with pinpoint accuracy using the grid-shaped layer system.
Advantages of PET layers
- lower thickness
- lower production costs
Disadvantages of PET layers
- Risk of diminishing transparency
- Limitation to display diagonals up to 15 inches
