Today, the terms "interactive screen" and "multi-touch" are used somewhat generically. Unfortunately, the selection for the right screen is rarely that generic. Let’s take a quick dive into the different tech used to navigate on screen. There are five prevalent touch technologies:
This is one of my personal favorites since the accuracy is very high and some versions have the capability of recognizing multiple users. This technology uses a wire mesh that is so fine your eye can not pick it out when the screen is on. Attached between a glass panel and the screen, it uses the electrical capacity of your hand; that interference is detected, and location of the touch is determined.
Projected Capacitive Touch;
Sometimes considered the newer version of capacitive touch with a bit more accuracy, it still uses a similar wire mesh. The electrical field is built up across the surface of the screen and can detect a finger or hand in a tin glove. The word "projected" is added because the electrical field is cast out above the surface of the screen.
This touch is less expensive but can influence the visual appearance on the screen. This technology consists of two wire mesh layers built into a film that is placed over glass (or a screen). The layers have a thin separation, and when touched by pretty much anything, the two layers compress at the point of contact and the resulting signal provides a location.
Surface Acoustic Wave;
I think this is one of the more interesting touch-technologies that uses ultrasonic waves. It exhibits great image quality, but heavy dust or dirt on the screen can cause issues. Basically, there are a few ultrasonic devices sending vibrations across the surface of the glass at different angles. These devices see the change in the wave caused by a finger-touch.
These allow for superb image quality, but they require a significant bezel that holds small cameras in the corners; larger screens would use multiple cameras along the edge. These cameras set up an invisible grid on the surface of the screen that calculate the touch location. Heavy dust can again be an issue, and bright ambient light can create problems as well.
The best touch technology to use? That all depends on the look, the environment, and the experience in which it will be used. Each touch technology has advantages and disadvantages as well as useful tricks.