Designing a Touchscreen: Where to Begin

Touchscreens are gaining popularity with manufacturers as an alternative to other switching technologies, and it is easy to see why. When it comes to user interfaces, touchscreens have successfully changed the way electronic equipment is used by simplifying the user experience and eliminating the need for buttons or keys. If you are considering incorporating a touchscreen into the design of your product, there are key items that you should consider.

First you should understand the difference between a resistive touchscreen and a capacitive touchscreen.

Resistive TouchscreenResistive Touchscreen Illustration

A resistive touchscreen is constructed using two clear conductive layers (typically a glass or acrylic substrate and a polyester top sheet) that are separated by insulating dots. When the user touches the screen and compresses the top flexible layer, electrical contact occurs between the top and bottom layer.

Capacitive TouchscreenCapacitive Touchscreen IllustrationRGB

Voltage is applied to the corners of a capacitive touchscreen and distributed by a pattern of electrodes located around the touchscreen periphery. This creates a uniform electric field across the conductive surface. When the user touches the screen with a conductive object (such as their finger), they are drawing a minute amount of current from the surface. This change in capacitance is measured at each point on the touchscreen allowing the touch position to be located.

Before you actually sit down and design your touchscreen, there are at least four main considerations you need to take into account:

  1. Environmental conditions
  2. Software requirements
  3. Firmware requirements
  4. Appearance

These will help you determine the materials and types of technology to utilize in your touchscreen. For each consideration there are a number of questions you will need to ask yourself:

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