Blog: The Past, Present and Future of Touchscreen Technology

October 16, 2017

Whether they appear in personal computing or in commercial products, we are in the era of the touchscreen. From smartphones and tablets to custom OEM designs, touch is now the industry standard. But for manufacturers, the uptake of touch technology has been a long time coming.


Past

1965 saw the first true realisation of the touchscreen by E.A Johnson, which was described in an article named ‘touch display – a novel input/output device for computers’ in Electronics Letters magazine. It outlined the early makings of technology we use today known as ‘capacitive touch’. 

For manufacturers, who may be otherwise unaware of how capacitive touch works and why it suits their product, they essentially use an insulator which is coated with a conductor like indium tin oxide. The human finger then works as an electrical conductor which is picked up by the screen. 

Despite this early description, the first touchscreens to rise to prominence were resistive touch, which were invented by Dr. G. Samuel Hurst out of need for a faster way to log research at the University of Kentucky. It was developed further into a method of interaction by adding a conductive cover sheet over a screen mapped with an X and Y Axis. Pressure on the sheet meant voltage passed between the x and y wires. This pressure is what gives ‘resistive’ touchscreens their name. 

The cost-effective nature of these screens coupled with the ability to use them with gloves, styli and in harsh environments has meant the technology is still in use today – especially in high stress environments like field service, construction and retail.

It wasn’t until the 80s that multi-touch technology was introduced, using a camera behind glass to track action as black spots on the screen. The camera output was then digitised and sent to a signal processor. 

This first innovation was the start of a decade of change – but it wasn’t until the 1990s that touchscreens became affordable enough for the general public. PDAs became popular, utilising stylus touchscreen technology. The consumer adoption of these devices proved to manufacturers that touch tech was here to stay.

In the new millennium, Sony introduced the SmartSkin, which could capture gestures by calculating the distance between a hand and the surface with capacitive sensing and mesh-shaped antennae. This was originally meant to turn tables and walls into touch controls for laptops, but because it could sense multiple contact points, the tech was the foundation of a capacitive revolution.  

Jeff Han, a US research scientist, debuted the first affordable high resolution multitouch screen in 2006 and eventually sold it to Microsoft, who produced the first table-top surface before going on to refine the technology in a partnership with Samsung. 

Present

Resistive (4-wire) touch is still used in some applications where there is a lot of dust and dirt in the room due to its sturdiness, but is now falling out of favour thanks to the decreasing cost of capacitive. This, conversely, has increased the price of 4-wire, although it is still cheaper than a capacitive system.

Most modern screens now use capacitive touch. However, the actual technology behind the screens differs. At its foundation, capacitive touch uses a layered structure whereby the electricity from your finger interferes with the screen’s electrical field, which registers as a touch. By introducing two separate layers, one using transmitter electrodes and one using receivers, multiple touch points can be used. 

As this technology was being developed, companies were beginning to optimise their software to better handle touch, such as TFT screens adding on-cell technology where the touchscreen mechanism is part of the screen itself. This meant improved responsiveness and reduced size. 

Where TFT screens use a backlight which passes through colour filters, OLED screens make their own light – hence their name. These provide superior viewing angles and better quality. AMOLED, a Samsung invention, added an active matrix to the technology which means the pixels can switch on and off, removing any ghosting. 

Future

The level of current access to capacitive touch means they’re used in virtually all smartphone or tablet technology – and quality is improving each iteration. Resistive touchscreens will shortly be a thing of the past as manufacturers have never had better access to low cost touch technology, with impressive TFT displays that are perfect for use in kiosk displays, instrumentation and navigation devices. As technology improves, AMOLED screens will become far more widely available – with our team predicting that it will be the leading screen option in two to three years’ time. 

Haptic feedback, which provides vibration and other tactile stimuli as you use the screen, is one area where touch is expected to improve. It’s forecast that users will eventually be able to ‘feel’ items and textures on a touchscreen, enhancing overall usability.

It must be admitted that touch technology will likely be disrupted by the rise of Virtual Reality and hologram tech, but the reliability and level of user friendliness that touchscreen offers means it will become a baseline technology rather than be replaced. The excitement of innovation may transfer to VR, but touch will remain the dominant format for wearables and personal tech.

For manufacturers, the key is to focus on the quality of the display and to introduce touch technology wherever possible. Users have come to expect touch as a minimum requirement and this will only increase as time goes on. Consider young children, who typically instinctively try and use touch when they encounter a screen. They are the next generation, and prove the need for touch as a baseline in all screens. The future will demand touchscreen in almost every device. If your products lack it, they may fall behind. 

 

Clive Dickinson is our business manager for Optoelectronics.

Follow Clive on LinkedIn.


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