While resistive touch screens were once the standard in industrial environments, PCAP touch screens are increasingly favoured for their superior optical clarity and scratch resistance.
Let’s look at how each type of screen works, and some of the pros and cons.
Resistive touch screens explained
Resistive touch screens screens work by using two transparent layers, each with a conductive coating, separated by a small gap. When pressure is applied to the screen, the layers touch, allowing voltage to pass and triggering a response at the point of contact.
This pressure-based operation is what makes resistive touch screens effective, even when used with gloves or a stylus.
However, resistive touch screens also come with some disadvantages, including:
- Typically support only single-touch inputs.
- Lack the optical clarity found in newer technologies.
- Prone to scratching by tools or heavy use.
- Can wear out over time, particularly in areas frequently touched.
- Can deteriorate when repeatedly exposed to sunlight and adverse weather conditions.
- Large screen sizes, above 24 inches, are rare due to manufacturing constraints.
Why PCAP touch screens are gaining in popularity
Made primarily from glass, projected capacitive (PCAP) touch screens offer higher optical clarity and improved scratch resistance compared to resistive screens. This technology works using a sensing layer under the outer glass. The sensing layer has small electrical currents running through conductive paths across the screen in two dimensions, and it detects the electrical capacitance between the vertical and horizontal current paths.
When a finger or conductive stylus is brought near to the glass, the electrical field is disturbed and the capacitance changes. The sensitive circuitry detects this change and registers touch positions.
Early capacitive touch screens could only detect when a bare finger physically contacted the glass. But newer “projected” capacitive technology now allows them to work with gloved hands and supports multi-touch, even with a thick layer of glass in front.
One critical issue that has plagued PCAP touch screens is how they handle water drops on the glass surface. As water can conduct electricity, every drop of water on the screen can cause it to feel a ‘touch’. This can severely disrupt the working of the computer as it registers hundreds of touches all over the screen.
Attempts have been made to work around this issue, and recent PCAP screens mostly tolerate having very small droplets on the screen. However the presence of water on the screen can still pose a challenge when using PCAP in very wet environments, or where water runs across the screen, such as outdoors in a storm. In this kind of situation, resistive touch screens are still sometimes called for.
Nevertheless, projected capacitive technology continues to advance, and the latest PCAP touch screens have overcome the challenges of working with thick gloves and in harsh environments. Improvements in IC controllers, drivers, and firmware have significantly enhanced their performance and accuracy. As a result, PCAP technology is now replacing resistive touch screens in many industries, offering more durable, precise and user-friendly solutions. They have also been adopted in healthcare settings, where gloved use is key.
ESIS and the latest technology
ESIS is a leading provider of industrial computing products designed for applications requiring high performance, reliability and long-term stability. We offer a wide range of modular, industrial Panel PCs and monitors, available in various sizes and CPU platforms to suit diverse needs.
The touch Panel PCs and monitors we provide are ideal for factory automation, smart manufacturing, robotics, real-time monitoring and process control. As PCAP technology continues to evolve, ESIS is committed to delivering cutting-edge solutions that improve operational efficiency in even the most demanding industrial environments.
At ESIS Industrial Electronics, we offer a range of solutions to meet your industrial user interface needs. Whether you require a rugged, high-quality display, a powerful integrated computing platform or a programmable interface for direct PLC integration, we have the right equipment to ensure your operations run smoothly and efficiently.
For more information, visit www.esis.com.au or contact our team to discuss your specific requirements.
