Touch Panels Just Keep Getting Better

By Arthur Berman
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The industry has seen the capabilities of Multi-touch Projected Capacitive Touch (MPCT) panels improve quite considerably during the past few years.  Nonetheless, it was a recent product press release by Itron that made clear to me just how far the state-of-the-art of this technology has progressed.  The company calls its latest technology MPC Touch.

Itron, a subsidiary of Noritake Japan, is known for developing display module hardware and operating systems.  In 1997 the company established a design and manufacturing operation in the UK.  The latest development and the press release comes from this source.

A key feature of the new panel is that it can work with up to a 4 mm plastic or an 8 mm glass overlay.  Most interestingly, it is reported as able to support applications where users are wearing a range of gloves from nitrile, nylon, cotton and leather. Presumably this comes at the expense of some reduction in touch resolution.

A second benefit of the new technology relates to the means of device assembly.  No bonding is required between the touch panel and the front overlay.  Rather, a 0.5 mm air gap is allowed.  The gap serves to prevent unwanted optical effects.  Depending on the front panel material, miniature corner spacers can be used to define the gap.  The fact that a gasket or bezel is not needed means that it is possible to achieve a flush design.

Another feature of the panel is that it has low impedance.  This, in turn, allows the use of compact flex foils making it possible to retrofit the sensors into existing applications.

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The touch panel is also claimed to have considerable resistance to high humidity and direct water splash.  Rain drops do not trigger a false response from the touch screen when the front panel is inclined to allow water to run off.  In fact, a wet touch panel will still properly interpret touch inputs even if the user is wearing gloves and….it will do so without any re-calibration.  This capability is illustrated in the video appended below this article.  Also illustrated is the fact that the panel supports up to 16 simultaneous touch, grab and pinch items.

The electrodes are deposited at a temperature of 300oC.  This gives the technology a wide temperature range starting at -40 oC.  The projected electrode life is in excess of 100 years.

Itron UK Managing Director Andy Stubbings stated that, “Unlike the conventional ITO PCT which requires significant tuning to suit the application, MPC Touch can use one threshold value for varying thickness of front panel material”.

Itron offers a capacitive touch controller module part number MCBK42 that is suitable for all sizes of MPC touch panel.  It provides host interface via asynchronous serial or twin wire I2C interface.  On-board linear and digital voltage regulation enables 3.3V or 5V power supply support.

Standard touch panels are available and designed to be the same size as many popular TFT displays.  Current standard panel sizes are 4.3 and 7″ with 3.5″ and 5.7″ sizes soon to be available.  Custom panels are also available up to a maximum size of 10.4″.  A purchase quantity in excess of 500/year is typically needed for a custom order.  The NRE for a custom panel is usually about £3500.  Semi-custom sizes can be cut from larger standard panels to allow short run or rapid prototyping.

Based on the technology’s track record, MPCT panels will likely further evolve.   Meko will follow developments and report on new product offerings. – Arthur Berman

 

Itron (USA – headquarters, Chicago, IL), 847-439-9020, marketing.ele@noritake.com