Rugged Decoded: Touch-screens

Jul 07, 2016 • FeaturesHardwareRgged DecodedhardwareruggedRugged Decoded

As we continue our series of features helping you decode the jargon and terminology of rugged device manufacturers, we turn our attention to one of the most important yet potentially fragile areas of any device, the screen. Kris Oldand takes a look at what some of the key screen technology developments mean exactly when it comes to selecting devices for your field service workers ...

 


 

Read more form this series here

 


 

We live in the age of the touch-screen. Indeed my own son, who is now an inquisitive three and a half year old with an obsession with the word why, really struggled to understand recently why when he swiped back fore on the TV it didn’t do anything.

In a world of smartphones and tablets touch-screens have become a universally understood means of interacting with a device. Whether it is inputting data or simply navigating through an operating system, I would put a hefty wager on the fact that anyone reading this article is both familiar and comfortable with using a touch-screen device, such is the prevalence of the technology today.

Touch-screens are an important, even critical part of the user experience of almost all modern tablets and smartphones.

Also, amongst handheld computers that for many years were the go to device for field service teams, touch screens are becoming more and more increasingly common, whether combined with a keypad like the more traditional form factor, or on their own as is appearing in new hybrid products such as the Gen2Wave RP1600.

The balance therefore between delivering a screen that is sufficiently capable of with standing drops and knocks, whilst maintaining high usability, is absolutely critical for a rugged device.

Yet at the same time, the screen is of course the potential Achilles heel and obvious weak spot in a rugged device.

 

The balance therefore between delivering a screen that is sufficiently capable of with standing drops and knocks, whilst maintaining high usability, is absolutely critical for a rugged device.

So lets look at some of the various options you may find in differing rugged devices when it comes to the screen and explore exactly what these options actually mean.

Capacitive vs. Resistive

Almost certainly the biggest debate when it comes to screen choices in rugged devices is whether capacitive or resistive screens are better suited for the task. But what is the difference between the two?

The older of the two technologies is resistive which relies on pressure to register input. This pressure can be applied by your finger, a stylus or any other object - think of the handheld computers that many delivery companies use, often covered in ink because when the original stylus is lost, the delivery driver often just uses a regular pen to collect a signature instead.

The big advantage resistive screens have over their capacitive counterparts is the fact that the operator can still use the devices whilst wearing gloves - as the input is dependent on pressure rather than the electrical current

Resistive touch screens consist of two flexible layers with an air gap in between and in order for the touch-screen to register input, you must press on the top layer using a small amount of pressure to make contact with the bottom layer. The touch-screen will then register the precise location of the touch.

 

Rather than relying on pressure, capacitive touch-screens instead sense conductivity to register input—usually from the skin on your fingertip but also from dedicated styluses.

Because you don’t need to apply pressure, capacitive touch-screens are more responsive than resistive touch-screens. However, because they work by sensing conductivity, capacitive touch-screens can only be used with objects that have conductive properties, which includes your fingertip (which is ideal), and special styluses designed with a conductive tip.

Initially one of the big advantages of capacitive touch screens was that they enabled multi-finger gestures - perhaps the most obvious example is pinching or stretching a document to zoom in or out. However, resistive touch screens have also supported multi-finger input for about three or four years now also.

The big advantage resistive screens have over their capacitive counterparts is the fact that the operator can still use the devices whilst wearing gloves - as the input is dependent on pressure rather than the electrical current being completed through a conductive material such as a finger.

An additional benefit is that light touch, such as rain landing on the screen, won’t register so the devices are far better to suited to being used in the wet.

Both of these factors are of course particularly useful in a number of field service environments.

However, another key factor for rugged devices is of course reliability and durability and in this respect capacitive touch screens have the advantage - especially in heavy use applications.

Also in terms of reliability, if a capacitive touch-screen does happen to become pierced or cracked it is still likely to function - think how many times you have seen someone using a smartphone with a cracked screen?

Resistive screens can have a tendency to eventually begin to wear down in frequently used areas. Such areas may be prone to becoming faded and may ultimately even become unresponsive.

 

Also in terms of reliability, if a capacitive touch-screen does happen to become pierced or cracked it is still likely to function - think how many times you have seen someone using a smartphone with a cracked screen?

However, a break anywhere on a resistive touch-screen will often mean that it no longer works.

In terms of field service this is a potentially huge advantage for capacitive screens as it allows for a field service technician to continue to utilise their device until they can get the screen repaired.

Going Gorilla...

A special mention here really needs to go to Corning, a specialist materials manufacturer based in New York whose Gorilla brand glass has achieved what very, very few component manufacturers have achieved by becoming a recognised brand beyond the confines of the technologically minded.

Other than chip manufacturer Intel, can you actually think of a component manufacturer with a brand you recognise? Such is the impact that Gorilla Glass has had on smartphone and tablet manufacturing, with devices ranging from Samsung’s latest consumer flagship smartphone the S7 Edge, through to the Motion F5M by Xplore Technologies rugged tablet, proudly declaring their use of the product. In fact Gorilla Glass has been designed into over 4.5Bn devices globally.

The process developed by Corning to create Gorilla Glass is to chemically strengthen the glass through an ion-exchange process that creates a deep compression layer on the surface of the glass substrate

The process developed by Corning to create Gorilla Glass is to chemically strengthen the glass through an ion-exchange process that creates a deep compression layer on the surface of the glass substrate and this layer essentially acts as “armour” to reduce the introduction of flaws.

 

Produced in thicknesses ranging from 0.4 mm to 2 mm, Gorilla Glass is positioned as an ideal cover sheet for touch-screens. It’s tough enough to handle the surface pressures intrinsic to these devices, and exceptionally thin to enable more sensitive and accurate responses.

However, a quick look at the spec sheets of some devices at the higher end of the rugged spectrum from the likes of Panasonic, Xplore, Getac, et al, will reveal that Gorilla Glass isn’t quite so frequently used amongst such devices.

One reason for this is that the whole point of Gorilla Glass is that it can deflect impact significantly without breaking and while extreme deflection seems on the surface like a great a great characteristic for rugged devices, once a Gorilla Glass touch panel is installed over an LCD and a point impact occurs, the Gorilla glass deflects and the impact is transferred to the LCD glass which could potentially break, leaving you with a an undamaged sheet of glass covering a no longer working tablet.

Visibility

Finally, whilst the ability to use a touch-screen in various conditions is important, being able to read the screen in direct sunlight is the other significant factor to consider for field service operatives - who will be often working outdoors.

The key terminology here that you will often find listed in the spec list of rugged device is a level of NIT. Basically a NIT is a unit of visible-light  intensity, commonly used to specify the brightness and it is the crucial the number to look for in device specs for devices that are used outdoors.

Anyone who will has tried to watch a movie on their iPad (iPad 4 is specced to 364NITS) at the beach will attest is not bright enough to use in direct sunlight. By comparison, the ultra-rugged Xplore XC6 boasts 1300 NITS

On average, your general consumer device will offer something between 300 and 400 NITS, which as anyone who will has tried to watch a movie on their iPad (iPad 4 is specced to 364NITS) at the beach will attest is not bright enough to use in direct sunlight. By comparison, the ultra-rugged Xplore XC6 boasts 1300 NITS, whilst Panasonic’s Toughbook 20 and Getac’s V110 convertible laptop both offer 800 NITS, which makes the devices far more usable in the direct sunlight.

 

Also, in addition to improved NIT levels, many rugged manufacturers also offer their own enhancements to improve visibility such as Xplore Technologies’ ‘View Anywhere’, Getac’s ‘sunlight readable technology’, or Juniper Systems’ ‘Sun-to-Shade’ solutions.

Of course, as with all other considerations around device selection for your engineers, an understanding of their workflow and working environment should be considered. Are they likely to be working in direct sunlight for example or are they likely to be wearing work gloves?

Such questions should shape your requirements when it comes to the type of touch-screen you require in your field service engineer’s devices.

 


 

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