Cross a Keyboard with a Touch-Screen

The move from physical buttons to touch-screens is seemingly complete. Aside from a few niche products and ‘dumbphones’ at the low end of the market, every major manufacturer has shifted to touch-screen technology. Even long-time holdout Research in Motion, creator of the BlackBerry, has made the leap.

There’s one feature that a touch-screen interface lacks, however: tactile feedback. Although there has been work on haptic interfaces, which use the vibration feature of smartphones and tablets to confirm button presses, there’s nothing like the physical feel of a button being pressed for touch-screen devices. At the Society for Information Display (SID) Display Week 2012 event, however, a technology designed to address that lack was unveiled.

THE TACTILE TOUCH-SCREEN KEYBOARD
Tactus isn’t a familiar name yet: established in 2008 in Fremont, California, the company has yet to bring a major product to market. There’s a good reason for that though – the technology on which the company is working is sufficiently novel that it’s having to break new ground every single day. The technology in question is a system for raising physical buttons from the surface of a touch-screen, giving it the tactility of a traditional button- based input device without sacrificing the flexibility of a flat touch-screen interface.

That’s an interesting enough proposition for investors to have put $6 million into the company in December last year, providing Tactus with the funds needed to bring its theoretical designs to life in a commercial ready package. Add in additional funding from the US National Science Foundation and Tactus had everything it needed to show off prototype devices at the SID event last month.

Dubbed the Tactus Tactile Layer, the company’s proprietary technology takes the form of a deformable membrane designed to replace a capacitive touch-screen’s traditional cover layer. Measuring just 0.7mm to 1mm thick and completely transparent, it’s almost impossible to detect the Tactle Layer when it isn’t in use; but, when activated, it makes its presence known in an impressive manner.

The Tactile Layer sits over a series of fluid- filled cavities, which use a branch of fluid mechanics called micro-fluidics to rise up on demand and create a bubble in the deformable membrane. This bubble, positioned to sit directly over the device’s on-screen keyboard or dial pad, provides a raised surface analogous to the physical buttons of a traditional keypad.

Like physical buttons, each bubble provides tactile feedback as it’s pressed. Pressure causes the ‘button’ to depress, with the Tactile Layer able to differentiate between resting pressure and active pushing – which a traditional capacitive touch-screen can’t do. This will be joyful news for anyone who has tried to touch-type on a tablet.

When the raised surface is no longer required – when the keyboard has been put away for a spot of web browsing, image viewing or gaming, for example -Tactus claims that the deformable membrane returns to its totally flat state and the substrate beneath turns completely rigid. Combined with the technology’s transparent nature, the result is a touch-screen that looks and feels like any other.

There are, of course, trade-offs involved with the introduction of any new technology. In mobile devices, the key concern is power draw, out Tactus claims that this isn’t an issue for the Tactile Layer. In tests, Tactus sawa peak current of 250mAat 3.3Vduring activation of the buttons – a process that takes just a single second to complete.

The Tactile Layer. Tactus explains in its white paper, only requires power when deploying or retracting. Assuming around 100 deployment of a tablet or smartphone’s on-screen keyboard a day, meaning 200 individual activations and deactivations of the Tactile Layer, a total power draw of around 13.89mAh is claimed. That’s less than 1 per cent of an average smartphone 1,500mAh battery’s lifespan.

However, will this technology ever see the light of day? Tactus believes that it will, and the company has physical prototypes -including a custom Android tablet-and a partnership with capacitive touch-screen giant Touch Revolution to reinforce its confidence.

Tactus still has some way to go before it can fulfil the true promise of its technology, however. Currently, the system is limited to providing fixed-shape buttons over a pre-defined keyboard or dial- pad area. The next generation of Tactile Layer, the company claims, will include the ability for manufacturers to specify abstract shapes – a directional pad for an on-screen gaming controller, for example – while the ultimate aim is to produce a version that covers the entire surface of the screen with a Tactile Layer grid, enabling almost any shape of button to be generated dynamically.

Tactus is currently silent about when the first products will be available to buy. With plenty of funding under its belt and a partnership with one of the largest producers of multi-touch displays in the world, though, it’s unlikely well be kept waiting for long.

1080P ON A 5IN SCREEN
LG Display’s stand at SID 2012 also drew attention for its demo of the company’s first 5in panel with a full HD1080p resolution. Although HD smartphones and tablets have been around for some time, the majority of them use the 720p (1,280 x 720) standard. The latest display from LG’s labs, however, scoffs at such half measures with a lull 1080p(1,920 x 1,080) resolution ina compact size that’s well suited to high-end smartphones.

Based on a variant of IPS called Advanced High-performance In-Plane Switching (AH-IPS), LG claimsthe display can offer significantly improved brightness at a lower power draw than the company’s existing 720p4.5in display, in addition to significantly enhanced colour reproduction.

It’s the resolution that’s designed to impress, however. Packing over 2 million pixels into a 5in 16:9 diagonal, the display features a pixel density of 440 pixels per inch (ppi). To put that into perspective, Apple’s much-vaunted ‘retina display’ panels, as found in the iPhone 4 family and the new iPac, feature significantly lower densities of 326ppi and 264ppi respectively.

The increased pixel density is important for more than just playing full HD video content at its native resolution too. The higher the pixel density, the less likely the human eye is to see individual pixels in an image. The high density at so makes text clearer and less tiring to read, while allowing detail to be discerned at smaller sizes – critical for web browsing on small screens. LG hasn’t announced when the display will appear in commercially available smartphones, but we expect to see something before the end of 2012.

BEATING APPLE RETINA
The final stand-out showing at the SID Display Week 2012 event came from Japan Display, and at first glance, it seems a little run-of-the-mill. With a native resolution of just 1.280 x 800, the company’s latest mobile-centric display seems dwarfed by the full HD monster unveiled by LG Display at the same event. However, unlike LG’s 5in screen, Japan Display’s version measures just 2.3in diagonally. The result is a world-leading pixel density of 651 ppi. which blows LG’s 44Oppi straight out of the water.

This impressive pixel density comes through the use of a film of low-temperature polysilicon transistors in the display’s Thin Film Transistor (TFT) driver portion. Operating at lower temperatures than their traditional equivalents, these transistors can be packed closer together; the pixel pitch – the distance between each picture element – of Japan Display’s prototype panel is an impressive 39um, or around half that of the company’s current best-selling model.

As with LG’s 1080p display, the claimed advantages are many. Japan Display claims that text is nearly indistinguishable from high-quality print on paper, while images are detailed enough to be mistaken for physical photographs – albeit photographs that are lit from behind. As with LG, Japan Display has yet to announce a commercial offering for its new display formal.

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Tags: Japan Display, LG, Tactile Layer