Apple patent reveals work on improved mobile touch screen

Work is being done to provide better iPhone and laptop interfaces

A recent patent filing by Apple shows the company is developing a way to create thinner, brighter touchscreens for its laptop and mobile devices, such as iPhone smartphones.

Today, touch-sensing components sit atop the layers that form a liquid crystal display (LCD) screen. In effect, Apple's invention aims to make the LCD pixels "touch sensitive" by eliminating the additional layers. By doing so, the screen becomes thinner, somewhat lighter, and brighter.

The filing for patent application 20100001973 was unearthed by the Patently Apple Website, which as the name suggests keeps tabs on patent filings, and therefore innovation, by Apple. You can find the full filing by typing in the patent number to the U.S. Patent and Trademark Office's search engine.

Drawings with the application show a "mobile telephone" and a "personal computer" (a notebook) to illustrate possible uses.

Of course interest in Apple's touchscreen capabilities is also high in light of speculation the company will introduce a tablet computer later this month.

The application, originally filed in late 2008, is credited to Steve Hotelling (Apple's touch technology guru whose team was responsible for iPhone's pathbreaking multi-touch screen), and to Shih Chang, Lili Huang and John Zhong.

It's widely believed that Apple uses mutual capacitance to create the iPhone's ability to sense, sort out, and interpret multiple touches on the display screen. Atop the LCD screen, a layer of nearly transparent material carries capacitors, which each store a tiny electrical charge that changes when you touch it. You can think of mutual capacitance as adding a grid to this capability: each touch generates a separate, distinct signal which is passed to the phone's processor. As a result, the phone can figure out the relative location and movement of several touches at once.

The newly disclosed patent filing would eliminate this separate layer by re-engineering the LCD screen, to create what the application calls "dual-function capacitive elements." These elements can form both part of the display system, to show an image, and part of the touch sensing system, to detect and interpret fingertip contacts. The result would be a "display with integrated touch sensing capability may be manufactured using fewer parts and/or processing steps, and the display itself may be thinner and brighter," according to the application.

Taiwanese-based Elan Microelectronics in 2009 filed a lawsuit charging Apple with infringing two of its touch screen patents.  According to a New York Times report, Elan said it previously won a preliminary injunction against another company, Synaptics, in a dispute involving one of the two patents cited in the lawsuit against Apple. The two companies eventually signed a cross-licensing patent agreement.

When Steve Jobs unveiled the first iPhone, the multi-touch interface stunned and amazed and delighted his audience. Yet the iPhone interface still only scratches the surface of what other researchers and companies are doing with multi-touch.

In the summer of 2006, nearly a year before the first iPhone was released, New York University scientist Jeff Han demonstrated a highly sophisticated multi-touch screen at the annual TED conference. You can see the video online.

In it, Han repeatedly talks about the conventional computer interface, including keyboards both physical and virtual, "going away" to be replaced by a direct, almost tactile manipulation of data and images.

Han is founder of privately-held Perceptive Pixel, whose Multi-Touch Wall product is perhaps best known for its use in 2008 by cable news network CNN.  You can see a more recent demo of Perceptive's product online.

LCDs themselves may be on the way out for mobile devices. Pixtronix, a Massachusetts startup and one of our 2009 Wireless & Mobile Companies to Watch, discards conventional LCD components and layers in favor of a radically simpler way to control light: a tiny, electro-mechanical shutter, one per pixel, that opens and closes in software-controlled sequences.

Pixtronix's PerfectLight Display passes 60%-80% of the light from the backlit display, compared to just 5%-8% for a conventional LCD, according to the company. That translates into full-speed, no-blur video with 24-bit color, a 170-degree viewing angle, and a 75% reduction in power demand, on mobile device screens that can be bigger and brighter with higher resolution.

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