Touchscreens are at the heart of a clicks-to-bricks customer journey. Customers love going shopping but retailers need to entice them through the door, and make them feel comfortable completing the transaction in store.
Their new digital tools: interactive windows, “endless aisle” displays, kiosks, touch tables – all rely on contact through a touchscreen – these days, most commonly through projected capacitive (p-cap) technology.
New touch controllers are raising the bar for performance and enabling new features in interactive video walls and touch tables. They offer a narrower inactive border in line with the trend for displays to be thinner with a maximum display area. Soft keys can be placed around the edge of the screen. Speed of touch response is improved dramatically. New functionality such as contactless payment, loyalty card recognition and even wireless phone charging can be added.
Improved noise immunity
The key to these improvements is the drive signal applied to the sensors’ Transmit (Tx) array of electrodes by the touch controller. The level of this signal is a classic trade-off, a low voltage signal can be overwhelmed by electromagnetic interference (EMI) from the environment, a high drive voltage can create interference in the sensor itself, which can potentially degrade performance.
Most projected capacitive touchscreen manufacturers are forced to use a Tx signal with a DC current of between 20-30V, due to limitations in available “off-the-shelf” touch control components and ASICs.
However, Zytronic’s new ZXY500 range of controllers has been purpose designed to operate at an industry leading Tx drive voltage of up to 40V, enabling full multi-touch detection in extremely challenging self-service and public use applications. The new controller features a unique ASIC (Application Specific Integrated Circuit), a custom designed silicon chip created by Zytronic.
The ASIC increases the speed of touch detection, updating touch co-ordinates in just 1ms at the controller output – helping to reduce touch latency by a third compared to the previous generation controllers, and improving the overall user experience.
Enhanced visual presentation
The higher drive voltages reduce the influence of noise on the data captured. A significant source of this noise is the proximity of the display behind the overlaying touch sensor.
With all larger projected capacitive touchscreens, it is necessary to have a gap (air or resin filled) between the front of the display and the rear of the touch sensor, and the new ZXY500 controller now allows this gap to be substantially reduced, depending on the size and type of display selected.
This not only enables the whole machine to become slimmer and more compact, it also reduces optical parallax between the display and the overlaying sensor, improving the user experience and perceived accuracy of touch.
The new controller also enables a substantially reduced non-active border to the sensor: to just 10mm for a 55” diagonal touch sensor. The border reduction has been achieved through proprietary new touch detection algorithms in the controller firmware which allow the Transmit (Tx) and Receive (Rx) electrodes in the sensor borders to be located far closer together without creating interference or “cross-talk”.
The ZXY500 controllers also make it possible to design “soft” keys around the edge of the dynamic active area of the projected capacitive touchscreen. These fixed touch “buttons” are managed by the same controller and their function can be defined by the designer – for example keys for dimming/increasing brightness or raising and lowering volume – all via the controllers firmware.
A further enhancement is the opportunity to include tactile feedback through the ‘force sensing’ capability. Zytronic has developed further custom touch detection firmware for the ZXY500 which responds to the increased surface area of a fingertip when pressed more firmly onto the screen and graduates its output accordingly. Software developers can then use the variable Z-axis coordinates from the controller to activate different functions depending on the applied pressure, such as issuing an audible message alerting the user to the option selected when the screen is touched lightly, and then confirming the choice when pressed harder.
Contactless payments and phone charging
The improved noise immunity of the new controllers allows useful additional functions like contactless payment, wireless phone charging and customer tracking close to the active area of the touchscreen, enabling a tightly integrated layout. The technologies used to implement these functions, such as RFID, NFC and Qi, generate signals that can interfere with the operation of conventional projected capacitive touchscreens, but the new controller has industry leading signal-to-noise ratios and sophisticated algorithms that change dynamically to reject electromagnetic interference in the operating environment.
Zytronic has tested each of these technologies with the ZXY500 controller and demonstrated that they can be implemented very close to active touch area without impairing the performance of the touchscreen.
System integration and communications
A key factor in the success of a user interface design is how easy it is to integrate the controller into the rest of the system. USB is an extremely popular interface, but there are some applications that require RS232, I2C or SPI interfaces, and the new touch controller also supports these communication protocols.
Size is also an important consideration, and the smallest projected capacitive controller in the new ZXY500 range has been significantly reduced in size to just 61 x 64mm to support Zytronic touch sensor sizes up to ~19”, with other controllers in the family covering touch sensors up to ~90”.
The flexible printed circuits (FPC) connecting the touch sensors to the new controllers have also been reduced to just 120mm in length, further simplifying integration.
For applications where space is at a premium, the new controllers are also available as a ‘chip set’. Under special agreement, Zytronic will provide the ZXY500 design files to a customer, and just supply the core ASIC and ARM Cortex microprocessor (with Zytronic touch detection firmware pre-loaded). The client can then embed the touch controller onto an existing motherboard within their system, saving space, cost and integration time.
Finally, the new controllers have been designed to be HID (Human Interface Device) compliant and offer ‘plug-and-play’ operation with later Windows operating systems, also supporting Linux and Android builds capable of multi-touch input.
Conclusion: A “phygital” experience
Retailers that get the customer experience and journey right are showing that it is entirely possible to run a thriving physical store alongside a successful online presence, and in doing so out-compete online-only resellers.
Customers enjoy meeting and interacting with knowledgeable and helpful sales staff, and the opportunity to see and handle the physical product – experiences that are simply unavailable online. By harnessing the best available touch technologies, however, it is much easier to bring the best of web into the store, and truly give customers the best of both physical and digital worlds.
