As industry keeps on moving towards signage, interactivity plays center stage as a prime instrument of customers’ engagement. It quickly becomes a key growth area for further developments. A variety of techniques used to communicate with users on large video walls includes crowd cameras, face recognition, interactive content changing, and of course touch technology.
The ubiquity of touch-driven handheld devices and information appliances make people project the same user experience to large video displays, including LED. Super tight pixel pitch displays introduced recently make it possible as never before.
However, applying a touch option to LED screens could pose a serious challenge. Due to the manufacturing process, their surface is grainy and rough to touch, and also easily broken because of the exposed pixels.
“Currently all LED manufacturers use Surface Mount Devices that have a lens. This lens provides some protection. The weakness is in the solder joints of the SMD to the PCB,” – explains Eric Li, CEO at SiliconCore. “As the pixel pitches get smaller, naturally the user wants to get closer and touch the screen. The SMD package is smaller and more of them introduce more points of weakness. Often we recommend a protective layer, either glass or touch overlay”.
Moreover, the risks of touching an uncovered LED screen could also include an unpleasant user experience of tactile feel or even an electrostatic shock, warns Romeo Estores, the product marketing manager at Leyard and Planar.
Until recently, putting glass in front of a display seemed quite an optimal solution. However, glass overlay has a lot of drawbacks that surpass its advantages of low price and easy affordability. Being heavy and bulky, glass often comes in fixed size sheets ruining the idea of a seamless video wall and creative design. In addition to that, it traps heat and reflects image causing parallax effect and a contrast reduction as a result.
To avoid the pitfalls of glass cover Leyard developed a new material, which they call a PLTS – Pliable LED Touch Surface.
“Leyard PLTS technology enhances the optical performance of LED video walls when compared to glass-covered interactive video walls,” – says Estores. “Parallax error is avoided and, with Leyard PLTS's antiglare properties, distracting reflections are eliminated. Additionally, the specially formulated, patent-pending material allows the LED video wall to maintain uniform color and brightness in direct and off-axis viewing”.
Described as a thin and slightly adhesive material PLTS literally rolls on to the front of an LED video wall creating a seamless anti-glare surface that feels natural to touch:
“Leyard LED MultiTouch with the Leyard PLTS surface material continuously spans across LED video walls up to 196" diagonal, creating a completely seamless interactive surface area,” – continues Estores. “The touch surface is an extremely thin, lightweight, anti-static material applied directly to the LED video wall, creating a protective, durable surface for multiple users to interact at once”.
Unlike fragile SMD, COB-based LED screens are mechanically more robust and rigid. The method of direct bonding of LEDs to the PCB results in a display surface, which is both solid and smooth. This makes it ideal for putting any kind of overlays or other types of screen material for touch.
COB-manufactured LISA is described as a disruptive technology that will change the way LEDs are being used now, says SiliconCore. Its increased durability will significantly expand the application area bringing in LED touch to signage applications like bus stops, malls, offices and QSR, believes Li:
“LISA will be more robust than previous LED displays, so the screen won’t require an overlay which will be a huge benefit for touchscreen applications. This will deliver a highly responsive touch experience; the capability to use touch outdoors and a very robust surface which can be used in digital signage and wayfinding applications. The major feature is that the LEDs will be directly bonded onto the PCB board and a user can touch the front of the display without damaging the LEDs.”
There are various touch technologies available on the market today. Those that provide two and more points of contact, e.g. multitouch enable multiple users’ session. These include resistive, projected capacitive, infrared, and optical touch screen.
Among those listed, infrared is the newest technology that reaches the highest precision of object detection, provides fast response time and perfect image clarity. Moreover, it is not bound to a screen size, which makes it suitable for large video walls. The technology is based on sensors that emit infrared light and are located in the corners of a screen. The sensors create a framework of infrared beams in front of a display. Once the grid is broken by a finger touch the sensors detect a point of contact.
That very technology is implemented in Leyard interactive LED video wall that offers 32 simultaneous touch points. However, the challenge of adding touch to direct view LED was not the sensor, points out Estores, but finding a way to simultaneously enable an interactive touch solution while also protecting the LEDs.
As a light-beam interruption based technology, Leyard LED MultiTouch is not a pressure-sensitive solution and, therefore, does not require direct pressing into the display, says Estores. Just a light touch would be enough to make the system work. Moreover, IR-based solutions can also work at a distance (Kinect) and smoothly recognize gestures, giving customers the ability to swipe, pinch with a finger, gloved finger, wet hand, stylus or pen.
As for LISA, the touch technology to a large extent will be dictated by the project and application, believes Li: “As a specialist in fine pixel pitch displays we work with and are agnostic to all touch screen manufacturers. We work closely with the integrator to specify the most suitable solution, whether for large scale displays with multiple users at once, up close, or in a corporate environment as a presentation tool. The system will be tailored to how many touch points are required, any environmental factors and the product it’s being applied to.”
According to SiliconCore, the technology will enable both direct pressing and work at a distance, dependent on the application: “We have worked on a number of applications including both gesture and touch projects, whether that’s gaming applications to encourage large participation in an interactive experience, corporate presentation suite or retail wayfinding. The application dictates the technology and in essence, anything is possible.”
The future of touch screens will see the abundance of new technologies that will be shaped by customers' needs, believes Estores: “There seem to be no bounds as to where new touch technologies will emerge in the future. It used to be that adding touch to a high resolution, fine pixel pitch LED video wall could be a compromise for end users but now that’s not the case. I believe what the industry sees now and will continue to see in the future are touch technologies that are specific to, perhaps even prescriptive too, the needs of the end user. Retail, corporate, museums, broadcast - these are all industries on the cutting-edge, and how they tailor touch technologies to their respective needs will be an exciting thing to see and be part of”.