Touch screen demo at TED conference
Jeff Han’s public demonstration of the multi-touch-screen interface was at the TED 2006 conference. The demo showed how, by touching the screen, the user could interact with the computer. This was one of the highlights at the 2006 conference. Since that unveiling, the interface has become the next advancement since the mouse. From now on the touch interface will become a standard way for a user to interact with a computer.
Over the last three years, users have been introduced to this user interface. Most notibly with Apples iPhone and iTouch consoles. Some of the new functions include how the screen is displayed and how the user can change documents being viewed. By touching the screen object and pinching the thumb and forefinger the screen zooms out. If you do the opposite the screen zooms in, enlarging the object. When you touch the screen with you finger and swipe to the left or right, a new page appears. This is similiar to using a mouse, but now a mouse is no longer needed.
This evolution of how the user interacts with the computer, is becoming more and more seamless.
Evolution of Touch Screen Technology
Touch screen technology was first developed in the late 60′s, but the first public systems were visible by 1972. These were generally point of sale kiosks and later into bank ATMs. The use of infrared transmitters and receivers continued the development of this technology. By this time the best sensors could only one point of contact at a time. With the development of heavy industrial machinery, the touch screen benefits, continued the development of the interface. It was used to interact with machinery with a mouse interface was not practical.
The branches of touchscreen technology
Surface acoustic wave relies on ultrasonic waves for touch detection. When the screen is touched, the change in the ultrasonic wave determines the location of contact. This disadvantage is that outside elements and contaminants will reduce the effectiveness of the interface.
Resistive touch screens use electrically conductive layers to determine the point of contact. Two thin layers separated by a small gap are built into the panel, when the location is pressed the layers are connected sending an electrical current to the controller. The method can support multi-touch systems.
Capacitive touch screen panels are another development. The panel is a sensor usually made of glass and coated with a transparent conductor. This type of sensor is styled as a capacitor in which the plates are the overlapping creating a grid pattern. Touching the surface of the sensor will affect the electric field alerting the computer that contact on the screen has been made. This touch screen process is used on Apples’ iTouch and iPhone. Other companies are Microsoft, Sony Ericsson, HTC, Palm and others.
Infrared uses LED and photosensor pairs to create a grid of light beams across the display. When a finger touches the screen the light beams are interrupted causing a measured decrease in light at the corresponding photosensors. The output can be used to locate a touch-point coordinate. The disadvantage is this system is the high cost and the interference of signals in outdoor, direct sunlight locations.
Optical Imaging is relatively new. The concept is that at least 2 image sensors are placed at the corners of the screen and infrared backlight are place at the other sides of the screen. When a finger touches this screen a shadow appears and the systems camera defines the area of interest. This method is gaining popularity because of its affordability and versatility. Continue reading →