location. A negative characteristic of the surface wave touchscreen was it’s influence to bad performance from external forces such as dust, water, loud sounds, etc. Anything that could distort the acoustic wave would potentially make the device fail. [6] Figure 5: Surface Wave Touch Screen Permission requested from itechcompany.com 2.3.3 Capacitive Touch Screens Another type of touch screen was the capacitive touch screen. There were several different categories in which you could classify a capacitive touch screen and they included surface, projected, mutual, and self-capacitive. Each of these technologies differed from the others, but the fundamentals of how they worked remained the same for all of them. A capacitive touch screen consisted of an insulating material such as glass, which was coated with a transparent conductor like indium tin oxide (ITO). A human finger was also an electrical conductor and when that finger pressed against the screen a change in capacitance between the two charges could be calculated and when sent back to a processor this could pinpoint the location of where the finger tapped the screen. Capacitive touch screens as seen in figure 6 had a considerable disadvantage to resistive touch screens in the sense that they must have a conductor such as metal or a human finger come in direct contact with them to select a location on the screen. This was an undesirable trait for consumer electronic devices where in cold temperatures a user might be wearing gloves or a woman with long fingernails might have a hard time getting the screen to operate correctly. Capacitive screens were in general more responsive than resistive screens, but were more costly and were impractical for this project. [ Figure 6: Capacitive Touch Screen Permission requested from eetimes.com 2.3.4 Infrared Touch Screens The infrared touchscreens used a simple design approach to deliver great accuracy and response. The screen used a grid of infrared and photo LED’s
location. A negative characteristic of the surface wave touchscreen was it’s influence to bad performance from external forces such as dust, water, loud sounds, etc. Anything that could distort the acoustic wave would potentially make the device fail. [6] Figure 5: Surface Wave Touch Screen Permission requested from itechcompany.com 2.3.3 Capacitive Touch Screens Another type of touch screen was the capacitive touch screen. There were several different categories in which you could classify a capacitive touch screen and they included surface, projected, mutual, and self-capacitive. Each of these technologies differed from the others, but the fundamentals of how they worked remained the same for all of them. A capacitive touch screen consisted of an insulating material such as glass, which was coated with a transparent conductor like indium tin oxide (ITO). A human finger was also an electrical conductor and when that finger pressed against the screen a change in capacitance between the two charges could be calculated and when sent back to a processor this could pinpoint the location of where the finger tapped the screen. Capacitive touch screens as seen in figure 6 had a considerable disadvantage to resistive touch screens in the sense that they must have a conductor such as metal or a human finger come in direct contact with them to select a location on the screen. This was an undesirable trait for consumer electronic devices where in cold temperatures a user might be wearing gloves or a woman with long fingernails might have a hard time getting the screen to operate correctly. Capacitive screens were in general more responsive than resistive screens, but were more costly and were impractical for this project. [ Figure 6: Capacitive Touch Screen Permission requested from eetimes.com 2.3.4 Infrared Touch Screens The infrared touchscreens used a simple design approach to deliver great accuracy and response. The screen used a grid of infrared LED’s and photo