A touch screen is a type of display screen that can detect and respond to touches from a stylus or finger. This technology has gained widespread adoption since Apple introduced the iPhone in 2007. Touch screens are now commonly used in various applications such as ATMs, retail point-of-sale terminals, automotive navigation systems, hospital monitors, and industrial control panels.
The touchscreen interface has become known for its user-friendly and intuitive nature. It allows users to interact with a computer system by directly touching the screen's icons, links, or other elements. This eliminates the need for external input devices such as keyboards or mice, simplifying the user experience and making it more accessible to a wide range of users.
The touch screen has revolutionized how we interact with computers and other devices, enabling more direct and tactile control. It has facilitated the development of intuitive user interfaces, making computing tasks and navigating the digital world more intuitive and efficient.
This component serves as the surface of the touchscreen that responds to touch inputs. Different types of touch sensors, such as capacitive, surface acoustic wave, and resistive, are used in various systems, including smartphones. In most cases, these sensors have a flow of electricity running through them, and when the screen is touched, the voltage changes. These voltage variations help determine the location of the touch input.
The controller is a hardware component responsible for translating the voltage variations detected by the touch sensor into signals that can be understood by a computer or other devices. It acts as an intermediary between the touch sensor and the connected device, converting the touch input into digital signals that can be processed.
A resistive touchscreen system consists of several components. These include the cathode ray tube (CRT) or screen base, a glass panel, a resistive coating, a separator dot, a conductive cover sheet, and a durable top coating. When pressure is applied to the top surface of the touch screen using a finger or stylus, the two metallic layers of the resistive coating come into contact, acting as a pair of voltage dividers with connected outputs. This contact alters the electrical current passing through the layers, resulting in a change in resistance. The touch event on the screen is then sent to the computer controller for processing. The pressure applied to the screen causes the conductive and resistant layers to come into contact, altering the resistance and generating the touch input.
Capacitive touch screens employ a different mechanism. They consist of a layer of capacitive material, which is a substance capable of storing an electrical charge. When a user touches the screen at a particular point, it modifies the charge at that specific contact point. This change in charge is detected by the capacitive touch screen system, which then registers the touch input. Capacitive touch screens are generally responsive to the electrical properties of the human body, specifically the conductivity of the user's fingers. They rely on the principle of detecting changes in capacitance to determine touch inputs.
In 1971, Dr. Sam Hurst, while working as a teacher at the University of Kentucky, invented a touch sensor called the "Elograph." This touch sensor, though not transparent like modern touch panels, was a significant advancement at the time. The University of Kentucky Research Fund patented the Elograph, and it was recognized as one of the 100 Most Important New Technological Products of the Year by Industrial Research.
Hewlett-Packard (HP) introduced the HP-150 in 1983, which was a home computer featuring touchscreen technology. The HP-150 incorporated a grid of infrared beams on the display to detect finger motions. However, the infrared sensors were prone to gathering dust, requiring regular cleaning.
The 1990s saw the introduction of mobile phones and handheld devices with touch screens. In 1993, IBM released the Simon, one of the first smartphones, which offered touchscreen capabilities. Around the same time, Apple's Newton PDA (personal digital assistant) was also released, featuring handwriting recognition and a touchscreen interface that allowed users to make phone calls. Palm entered the market with its Pilot series, which pioneered touchscreen technology and played a significant role in the PDA industry.
These milestones in the 1960s, 1970s, 1980s, and 1990s mark key advancements and introductions in the evolution of touchscreen technology, shaping its development and paving the way for the touchscreens we use today.