Thesis - Teknisk Design

Back to the general capacitive touch screen, in comparison to the others touchscreens, it has the advantage of being able to be cleaned with fabrics with nocommand input. It is also more responsive than resistive touch screen, otherwise isless accurate than resistive and more costly. There are some weaknesses due to thetechnology in which is based the capacitive touch screen. These are the possiblefailure even when few amount of water is involved, the less wide range oftemperature functioning and the need of at least five per cent of humidity to work. Ithas to be highlighted the fact that only capacitive stylus can be used in that type oftouch screen and that hands covered by glove do not have a response as ageneral fact in the capacitive touch screen (Barrett, G. L. and Omote, R. 2010). Allthe characteristics given for each touch screen and its classification amongcapacitive touch screens can be found in the figure 2.1.Figure 2.1 Types of capacitive touch screens.INFRARED TOUCH SCREENSThe technology used in infrared touch screens as its name says is infrared beams.There is an X-Y array of infrared LED and photodetectors pairs around the edges ofthe screen. The photodetectors detect a disruption in the pattern of LED beams topick up the exact location in which it has happened (Dhir, A. 2004). There are twotypes of infrared touch screens.Optical sensitiveOptical sensitive uses infrared beams that are invisibles for human eyes. The maindrawback is that strong ambient light could have a bad impact on its productivity(Mobile88.com, 2011).Heat sensitiveThis kind of technology is not often used for screens but for tactile buttons. It uses thechange in heat to determine the touched point. The worst fact of this technology is12