A Decade in Touch Display – and the SigmaSense Revolution

There are literally no limitations” Bill Dunn, LG-MRI Chairman

Thanks to the ubiquity of smartphones and tablets, everyone of all ages inherently expects most displays to now be touch enabled. The same thinking applies to large format (55”-98”) Digital Out of Home (DOOH) displays, which is LG-MRI’s dominant product line.  With SigmaSense’s SDC100 touch controller, we can now integrate touch sensors (also known as touchscreens) into all our displays with the confidence that we will achieve the world-class performance as expected from LG-MRI displays.

LG-MRI began our touch sensor journey in 2009 and when we deployed our 1st outdoor large format (72” diagonal) interactive touchscreen display in bus shelters in San Francisco in 2010.  This was a single touch product with a 30Hz update rate and barely more than 1 dB of signal-to-noise ratio.  There was no gesture capability; one finger point and touch only.  While it was revolutionary at the time and considered a technological and economic success, it was a user-experience nightmare.

Touch sensitivity was the biggest issue. The touch controller could only handle / detect one (1) touchpoint at a time and momentarily “locked up” if there was more than one touchpoint at any given time on the screen.  The touchscreen would not work with gloved hands or covered fingers and was very flaky / unresponsive in the rain, a problem in San Francisco. The touch controller indicated touches in the wrong spatial location, or indicated multiple touches for every single touch, also known as false touches. For the user experience, the response times and update rates were awful at 30 Hz.

Then, we realized the many environmental and climate issues which meant that every serial number required specific and frequent “tuning.”  Changes in ambient temperature, humidity, and the number of people in proximity to the touchscreen caused the touch to self-activate or not work at all.  Alignment and scale of the touch position in relation to the video image would also drift and require re-calibration.  Approaching and departing electric city buses would cause the touchscreens to have bursts of high frequency false touches due to electro-magnetic interference resulting from the arcing of the overhead electric cables and pantograph powering the bus.

Engineers at LG-MRI have spent the past decade trying to find an acceptable or better solution. LG-MRI has literally evaluated every available outdoor touch sensor technology, such as IR, micro-mesh, micro-wires, and ITO (indium tin oxide). We researched every available potential touch controller, all of which were analog and with an amplitude threshold based with, at best, 30Hz update rates, with constant drift and poor signal to noise ratios. This research concluded in LG-MRI developing a near-optically perfect index matched ITO all-glass touch sensor and we teamed with SigmaSense to bring their SDC100 current mode / frequency based software defined sensing digital (not analog) touch controller to the large format outdoor display market.

First and foremost, the SDC100 is the only large format display touch controller that works with or without gloved hands in any combination of outdoor environments: rain, snow, direct sun or shade.  For the first time in the age of touch technology, there are literally no limitations.  SDC100 opens every conceivable opportunity for high-quality, responsive and high-speed touch applications.

Second, the SDC100 is the only touch controller that provides the touch, feel, and responsiveness of a 5”-10” smartphone or tablet on a 55” to 98” large format display.  To achieve the same fluid responsiveness of a smartphone or tablet, the update rate of the touch panel must increase by the ratio of the size increase of the display.  Which means a 100” display touch panel must be updated ten-times faster than a 10” display touch panel to have the same emotional response and pleasing fluid interaction as a smart tablet.  The industry standard for smartphones and tablets is 30Hz; the SDC100 touch controller can update the touch hits on a 100” display at 300Hz.  Today, there is no other touch controller in existence with this unique capability.

Finally, there is our industry-proven capacity for quality control and software updates. LG-MRI provides a premium, durable product with the industry’s only 10-year performance guarantee, even when operated 24/7 in any global outdoor environment.  We have tens of thousands of products deployed around the planet on every continent other than Antarctica.  This means all of LG-MRI’s components, especially the touch controller and associated touch sensor, which provides the human interface to our products, must be robust, resistant to electronic interferences, long lived and capable of being monitored and updated using IP connectivity from any of our global NOCs (Network Operational Centers).

Prior to the SigmaSense SDC100, we had none of these capabilities.  We could not tell if the touch panel was functional or not. Is it scaled properly, or is it having false touches? Our only feedback was complaints from customers, which resulted in a dispatched technician to the reported faulty touchscreen display, often with mixed results.  Part of the remote IP capability of the SigmaSense SDC100, LG-MRI’s NOCs can see all touch controller performance parameters, download software updates, run diagnostics, and resolve problems remotely.  We have gone from being completely “touch sensor blind” to have full remote visibility and control.  This degree of remote visibility, diagnostics, and updates is realistically the only way to scale and grow a global deployment of touch enabled large displays in public venues. Interactive Touchscreens are becoming part of our everyday life and they must simply work flawlessly in all environments with all applications.

The new SDC100 digital Touch Controller is a dream come true, solving all of the negative issues of the past decade: >30 db touch signal to noise ratios, 300Hz update rates, full performance in any outdoor environment (rain, snow, direct sun, shade, freezing cold, blazing hot), no serial number by serial number tuning, no instability, no drift, and no false touches in high EMI environments, including proximity to high power arc welders. All of these features with 60,000 simultaneous touch points. Truly a transformative revolution in large-scale touchscreen displays.

All of LG-MRI’s displays, in any size up to 98” diagonal, are now designed to be touch capable.  LG-MRI now confidently offers these touch enabled products to any customer in the world regardless of the intended operating environment or geographical location.  Previously, we intentionally limited global distribution in quantity, location and environment to ensure reasonable deployment and support.  With the Sigma Sense SDC100, these limitations have now been eliminated allowing touchscreens to be utilized in all environments.