Images depicting the different technologies are courtesy of planarembedded.com
Resistive (Pressure sensitive) touchscreen:
As we’ve mentioned above, this is the most widely used touchscreen scheme for the production of mobile phones. It is most common in the Windows Mobile Professional phones, for example HTC TyTN II or HTC Touch Diamond; it is resistant to water and dust, but it is easily scratched and cannot be used with sharp objects. It is represented by three types: 4-wire, 5-wire and 8-wire with the second one being the most used. In contrast to the other types it is composed of three layers, rather than two with the additional layer ensuring greater durability and a much longer life (35 million clicks, instead of 1 million), without impacting the price.
Capacitive (Electrostatic) touchscreen:
Lately, this type of technology has been gaining popularity in the mobile phone industry, its most renowned representatives being Apple’s iPhone and LG PRADA. The smaller market share of phones with such screens is due mostly to their high price, since this is not a cheap method. It has two main subtypes, one of which cannot register more than one touch at a time, while the other, called „MultiTouch” by their creators (Apple and used in iPhone and iPod) can. In addition, despite not being the first to employ it, these two devices made this type of technological method popular.
Infrared (IR) touchscreen:
Samsung SGH-E900 and Samsung U600, which can only be touched with warm objects (e.g. fingers). Unfortunately, you’ll be unable to operate the phone if your fingers are “frozen”, because of cold weather.
The optical technological method uses infrared beams, which are not visible to the human eye and its only representative among the mobile phones is Neonode N2. It works, using a number of sensors, arranged above and around the screen, forming a grid of invisible beams. If an object (e.g. a finger or a stylus) touches the display, it interrupts the rays in a certain area and thus the touch point is determined. For this system it is not necessary to use physical force and just a gentle touch is enough. 100 % of the light, emitted by the display, is let through and its life depends only on the sensors’ lives, which spans for about 7 years of being constantly lit up. Further on, it is not influenced by dust, moisture or scratches, since actually the display’s glass simply shows the picture, while the sensors above it do the rest. However, a rather big disadvantage of this type of technology is that a strong ambient light can have a negative impact on its productivity and precision.