Most Desirable Mobile Phones 2008

Touch Screen Technologies in Mobile Phones

Mobile Phones with Touch Screen are available in the market for a long time. But they were never in so much demand as they are in today after launch of Apple iPhone. Apple’s iPhone created a new level of user experience with its ground breaking UI design and application environment. And thus it also increased demand for mobile phone with touch panel. Nowadays you can see bunch of phones coming with touch screen. HTC, RIM, LG, SAMSUNG, everyone has touch screen in their feature list. I was wondering, How this touch screen technology works? I was amazed to find out that these touch panel works on different methodologies. Here I am sharing some of touch screen technologies:

Capacitive Touch screen Technology

This system employs transparent metal oxide coated glass substrates. A voltage is applied to the corners of the overlay creating a minute uniform electric field. When touching the screen with an object emitting a constant electric flow, for example a human finger, a change in the current occurs and creates a voltage drop. Touch Screen controller measured voltage drop to determine touch location. A big constraint is that this screen cannot be activated by contact with inanimate objects (e.g. the gloves that you might be wearing). Apple’s iPhone, T-Mobile G1 and LG PRADA have used this touch screen technology. This technology comes in two types; Single Touch and MultiTouch.

Resistive Touch screen Technology

Resistive touch screen is composed of a flexible thick polyester cover sheet and a bottom layer of resistive metallic oxide coated glass panel. These two layers are separated by transparent insulating dots. Pressing the screen with a finger or stylus will make a circuit switch at point of contact. The two layers have alternate voltages between them and that’s how touch screen controller computes the XY coordinate of the touch point. Nokia 5800 XpressMusic (aka the Tube), HTC TyTN II, HTC Touch Diamond have used resistive touch screen technology for their touch panel. This technology is very cost effective and comes three types: 4-wire, 5-wire and 8-wire with the second one being the most used.

Infrared (IR) Touch screen Technology

IR screen uses the method to scan infrared systems; it works, using a number of sensors, arranged above and around the screen, forming a grid of invisible beams. A touch is registered when a finger or stylus encounters an array of infrared beams. The infrared technology is comparatively expensive technology and thus not so popular in mobile phones. Neonode N2 used IR for touch screen.

Apple Sued Over IPhone Touch Screen

I came across following article on WALL STREET JOURNAL regarding another case on Apple. This time a real estate developer claims to be the inventor for touch-screen feature and navigation mechanism of iPhone. Here is the abstract from the original article.

For those who thought Apple invented the iPhone, Elliott Gottfurcht of West Los Angeles has a surprise. The West Los Angeles real estate developer contends that he, not Apple, is responsible for technology behind some of the popular gadget’s fancy touch-screen and Web navigation tricks.And now he wants Apple to pony up. In a lawsuit filed in U.S. District Court for the Eastern District of Texas, EMG Technology LLC-a new firm that has Gottfurcht as a managing member-said it was seeking unspecified damages and an injunction against Apple, basing its case on a patent it was just granted in October. EMG is just the latest company to go after Apple, whose 3G iPhone has been enormously successful, selling 6.9 million units in the most recently reported quarter, which ended in September. But the case also shows how the patent system has evolved, making it easier for plaintiffs to file a claim.According to Stanley Gibson, a lawyer for EMG and partner at Jeffer, Mangels, Butler & Marmaro, the original patent was filed in November 1999, but EMG itself was established only this month and has no other business besides the patent at issue.[...Read Complete Article...]

I am not sure about this person's credibility but it would be interesting to watch further development in this case. I am sure Apple must have something in their pocket and they will hit back very soon.