Controller IC allows curved touchscreens in industrial and automotive designs

A series of touchscreen controllers from TouchNetix enables display user interface designs featuring curved and contoured overlays, hover and proximity functions, force sensing and integrated haptics control.

The first in the company’s aXiom series, the aXiom AX310 is the industry’s first touchscreen controller to be designed specifically for industrial and automotive applications, says the company. It says it is a superior alternative to the modified consumer-grade touchscreen controllers supplied to the industrial and automotive markets today. It enables OEMs to design responsive touchscreens that have a thick, varying-thickness or contoured overlay while maintaining uniform sensitivity across the whole screen’s surface.

It also enables them to implement hover, proximity, touch and concurrent force-sensing functions with a single capacitive touchscreen controller which also integrates haptics control to realise 3D touch effects.

OEMs can also support touchscreen designs in arbitrary and non-standard display formats, including ultra-wide aspect ratios and non-rectangular form factors and achieve reliable touch-sensing performance in the presence of multiple high-power noise sources.

The aXiom AX310 also enables OEMs to meet CISPR25 Level 3 specifications for radiated emissions without implementing expensive noise counter-measures and to reduce the risk of early touchscreen failure due to materials degradation in hot and humid environments, continues TouchNetix.

The aXiom controllers have been designed for use in harsh and noisy industrial and automotive environments and over a wide temperature range. It combines an analogue front end which uses a narrowband, low-voltage sinusoidal drive waveform, an innovative seamless frequency-changing capability to avoid noisy frequency ranges, and a proprietary DSP engine. The architecture has a high signal-to-noise ratio (SNR) of 80dB, typically, competing products have 50 to 55dB SNR, points out the company.

This high SNR is enabled while driving the sensor at a low DC-neutral 2.5Vpk-pk, whereas other controllers often use a drive voltage of +30V or higher to achieve even a modest SNR, explains TouchNetix. The aXiom IC’s low drive voltage produces very low levels of radiated emissions. The DC neutral bias also reduces the stresses experienced by the touchscreen materials. High drive voltages can result in in optical damage, and even metal migration, in the sensor material leading to premature failure of the touchscreen sensor stack.

The high SNR also enables reliable multi-point touch sensing through thick overlays, including acrylic thicker than 10mm or with an air gap in the stack, and even when the user wears gloves. Touch response to wet fingers, or when the screen is wet, is also superior to that of existing touchscreen controllers.

The powerful DSP engine enables micro-adjustment of the sensitivity at each node in the sensor matrix. The screen’s touch-sensing behaviour can be tuned regionally to provide uniform responsiveness to touch across a screen with an overlay of variable thickness.   

The aXiom controller can also perform capacitive proximity sensing at a distance of up to 100mm, and coarse position sensing of a finger as much as 60mm from the screen to support hover and proximity functions in touchscreen UIs.

The AX310 integrates concurrent force sensing and haptics control, to allow the touchscreen to guide the user’s finger through space to their chosen button, touch it, and only register a button press when force is detected at the button’s location. The AX310’s high-performance force-sensing measurement engine detects displacement of as little as 5micron.

The aXiom controller ICs support touchscreens with up to 56×56 sensing channels, and touch and force-sensing sampling rates of more than 200Hz. They are suitable for use with displays bigger than 15.6-inch diagonal, and in non-standard form factors and arbitrary aspect ratios. TouchHub development software is provided with the aXiom controllers to ease the design and tuning of touchscreen designs.

The AEC-Q100 Grade 2 qualified AX310 is available for sampling today.

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