Armed with a capacitive type multi-touch screen technology, ultrabook PCs are the first portable PC of its kind that allow people to tap the screen, or an on-screen virtual keyboard with their fingers not only to open on-screen files or menus, but also type into data.
Marking the first improvements in the UI or user interface in more than 20 years since graphics-based Windows OS replaced text-based and command-driven MS-DOS in early 1990s, the ultrabook PCs are signaling that the multi-touch screen technology will likely be a killer app to revitalize long-idle PC demand.
That might be welcome news for multi-touch screen microcontroller, or MCU IC makers, as they will open up new market opportunities.
To deliver on the market opportunities, however, they have to tackle a daunting technological challenge to make MCUs more noise-proof.
Of particualr, as more and more of touch screen modules are now being directly integrated into a LCD, or AMOLED display module, touch screen MCU makers are working on every possible way to make their product line-up less vulnerable to noise.
Coming complete with MCUs, ITO film or glass sensors and other functional components, touch screen modules so far have been stacked on the top of LCD, or AMOLED panels. Today, the traditional way of on-stacks is increasingly giving way to what’s called as an in-cell, or on-cell system, which requires touch screen modules to be integrated into the polarizer of a LCD panel.
The in-cell, or on-cell system gives thinner form factors, and cost less, compared with the traditional stacking methodology, but is very much susceptible to noise, because the touch module gets far closer to display panels
Cypress Semiconductor Corporation broke though the noise challenges with what’s called as a Gen 4 microcontroller chip. Released in December 2011, the Gen 4 chip is the 4th generation of its TrueTouch microcontroller product line-up, which is built with its two proprietary noise-cancelling technologies.
“The Gen 4 chip is what we think has the industry’s best performance in terms of noise cancellation. As you know, touch screen modules have two major noise sources. Charger noise and display noise are the big problems. Especially, the LCD panel form factor gets thinner, so that the center is closely proximate to displays. Then, you get a lot of noises,” said Christi Juchmes, product marketing specialist with Cypress Semiconductor.
“We have a very special and proprietary algorithm that essentially listens to noises and then calibrates them with our chip to reduce display and charger noise, “ added she.
Trademarked as Display Armor, for example, one of the proprietary technologies takes display noises out of the picture using built-in hardware to detect and silence noise regardless of display types.
Another indigenous technology, which is trademarked as Charger Armor, pulls the plug on the charger noise by listening for charger noises and activating when noise surpasses a configurable threshold. It eliminates both periodic and broadband noise for unmatched charger noise immunity.
All combined, these two proprietary technologies make the Gen4 chip a perfect fit for on-cell and in-cell integrated stack-up designs.
The Gen 4 chip also has the industry’s highest SNR, or signal-to-noise rate of 10V Tx as well as the fastest refresh rate of 400Hz –the measure of how fast and smooth it tracks input signals. The company has another proprietary technology trademarked as Tx-Boost, which can triple the SNR number without digital filters and expensive components.
Moreover, the Gen 4 chip consumes just 2mW (milli-watt) in active mode in what the company said is the industry’s lowest power consumption, while boasting 0.2mm both in an accuracy and multi-finger linearity.
Based on a 32-bit ARM processor, the Gen 4 chip supports a wide range of screen sizes from 1.5-inches to 12.6-inches. Mass-production of the Gen 4 chip was scheduled to start in early 2012.
To keep up with growing market demands for thinner form factors and lower manufacturing costs, Cypress Semiconductor also unveiled another groundbreaking technology, which is trademarked as SLIM, or slim single-layer independent multi-touch.
Dubbed as the world’s first true single layer multi-touch sensor, the SLIM has only one layer of ITO films coming with no bridge and no connector, allowing touch screen module makers to cut costs and thickness in half, compared with multi layer ITO film sensors. Powered by its TrueTouch Gen 2 and Gen 4 MCU chips, the single-layer solution can support screen size of up to 4.5-inches, being used with feature phones, portable media players, digital cameras, and GPS system. Especially when it comes to a screen size of up to 3.5-inches, the solutions enables module makers to build bezel-less touch screen.