In today’s technology age, touchscreens are a standard part of everyday life, with most consumer devices – including our phones, watches and even kitchen appliances – having some kind of touch function. In computing, touchscreens have become increasingly popular, but what technologies are available and how does ruggedisation impact screen selection? We find out more about types of touch panels available.
Ever since the transformational introduction of the Apple iPhone in the 2000s – which effectively saw touchscreens replace physical buttons on phones – there has been a shift in how humans interact with machines.
Many devices now offer a touchscreen functionality to simplify operation and improve software/interface navigation, often being more intuitive than using peripherals or buttons. The interaction is normally via a finger, or using some kind of stylus, depending on the application.
Of course, the iPhone was not the first instance of touchscreen technology – it has been around for many years. GRiD Systems Corporation – the legendary predecessor to GRiD Defence Systems – was a leader in this area and developed the first pen-and-display tablet computer, the GRiDPAD 1900.
The GRiDPAD 1900 development was led by Jeff Hawkins at GRiD, who went on to form Palm Inc., which developed the famous Palm Pilot “Personal Digital Assistance (PDA)” devices that included touchscreens and were the prelude to the smartphone era. Who’s old enough to remember those days?
Read more about GRiD’s history of innovation and our 30th anniversary here
How do touchscreens work? Capacitive and resistive technology
Early touchscreen devices like the GRiDPAD 1900 and Palm Pilot had a basic single-touch functionality, owing to the technology available at the time.
This touch-sensitive display technology is known as a resistive touchscreen, but what is it exactly?
This technology is normally made up of two resistive-coated transparent layers separated by a small air gap. When the resistive screen is pressed by an object – a finger or stylus – the layers make contact and complete a circuit, a device touch controller then calculates the coordinates based on the change in resistance on the display.
This allows a user to push on-screen buttons and interact with the device without using peripherals such as a mouse and keyboard. It is also worth noting that this is a passive technology and can be fitted over a device’s existing screen.
Capacitive touchscreens, meanwhile, are likely what most device users are now familiar with and were made possible by innovations such as the iPhone, which included Projected Capacitive Touch (PCT) technology.
Compared to resistive screens, PCT offers a more intuitive touchscreen experience with a light, no-pressure touch required to interact with a screen, which might include moving a cursor or dragging objects smoothly across a screen.
But how do capacitive touchscreens work exactly?
Unlike resistive screens that use an air gap, capacitive screens function by detecting changes in the electrostatic field on the screen’s surface induced using a conductive human finger, or multiple fingers – the latter enabling multi-touch functionality.
A capacitive screen is made up of a transparent conductive layer arranged in a grid of rows and columns (a matrix), and at each intersection a small electrical field exists. When these fields are disrupted through a finger touch, a minute amount of charge is drawn. A touch controller then measures the change in capacitance to determine the position.
Should I go with capacitive or touchscreen technology
When considering both types of touchscreen technologies for your device, it is important to consider what application you will be using it for. As we have already seen, capacitive screens offer a more intuitive touchscreen experience, and one that replicates what most of us are used to with existing smartphone technology.
However, there are downsides to capacitive screens – especially for rugged devices being used in military or industrial applications. One negative, as we will all be aware of from our consumer devices, is the capacitive screen’s poor performance in rain and adverse conditions. Water, moisture and dust have the effect of introducing unintended changes in capacitance, meaning inputs can be wrong or missed.
This is not ideal for those users that rely on rugged devices in outdoor environments, especially the military where touches could be mission critical. Military and industrial users also often use heavy-duty gloves, and once again capacitive touchscreen technology is not suitable for this.
Due to the nature of the technology, capacitive screens also emit electromagnetic interference, which means they perform poorly when it comes to strict electromagnetic compatibility (EMC) testing. This may not impact consumers, but is a key consideration for military users.
Electronic noise: why EMC compliance is critical for military computers
While resistive touchscreen technology may not offer the responsiveness and smoothness compared with capacitive, it is ultimately seen as the best option for rugged applications, especially for the military.
Resistive screens are weather tolerant, can be operated with gloves on, and perform significantly better in strict military EMC testing. This is the reason that customers for GRiD rugged computers choose devices fitted with resistive touchscreens over capacitive.
The future of GRiD touchscreens
At GRiD we are always seeking ways to innovate and leverage the latest technologies, and in the touchscreen space this is no different. In the past few years we have begun to introduce new multi-touch resistive screens into our devices, bringing together the functionality of capacitive screens while retaining the rock-solid reliability of resistive.
This multi-touch capability enables pinch-zoom and map navigation functionality, for example.
GRiD also continues to explore advances in material technology, which will improve our touchscreen products further and enable a better end user experience. This includes moving from thin glass to scratch-resistant polycarbonate plastics, greatly increasing durability. Modern plastics are also now designed to resist yellowing from sunlight, which again improves the user experience and product lifecycle.
It is also important to note that if a customer does not want touchscreen functionality, for whatever reason, this is also possible with GRiD devices. Some users in dynamic environments often complain that a touchscreen will hinder their operations through mistaken touches, so it is possible for customers to have a traditional non-touch screen if required.
As a UK-based device OEM, GRiD has the flexibility to design and build a laptop or tablet for the specialist application required – touchscreen or not.
Conclusion
From the very first pen-and-display tablet to today’s advanced systems, GRiD has a long history in developing state-of-the-art tablet and laptop solutions with integrated touchscreen technology. Today, we are specialists in providing highly-rugged, military-grade solutions with touchscreen technology – with particular expertise in resistive screen technology. These touchscreen devices offer multiple benefits to military end users operating in the harshest environments.
Looking to find out more about our touchscreen tablet and laptop technologies? Contact us for more information: sales@griduk.com.
