![Ecobee4 on the wall from an angle showing home screen](https://upload.wikimedia.org/wikipedia/commons/8/8c/Ecobee4_on_the_wall_from_an_angle_showing_home_screen.jpg)
A touchscreen or touch screen is the assembly of both an input ('touch panel') and output ('display') device. The touch panel is normally layered on the top of an electronic visual display of an
information processing system
An information processor or information processing system, as its name suggests, is a private content (be it electrical, mechanical or biological) which takes information (a sequence of enumerated symbols or states) in one form and processes ( ...
. The display is often an
LCD
A liquid-crystal display (LCD) is a flat-panel display or other electronically modulated optical device that uses the light-modulating properties of liquid crystals combined with polarizers. Liquid crystals do not emit light directly but in ...
,
AMOLED
AMOLED (active-matrix organic light-emitting diode, ) is a type of OLED display device technology. OLED describes a specific type of thin-film-display technology in which organic compounds form the electroluminescence, electroluminescent materia ...
or
OLED
An organic light-emitting diode (OLED or organic LED), also known as organic electroluminescent (organic EL) diode, is a light-emitting diode (LED) in which the emissive electroluminescent layer is a film of organic compound that emits light i ...
display while the system is usually used in a laptop,
tablet
Tablet may refer to:
Medicine
* Tablet (pharmacy), a mixture of pharmacological substances pressed into a small cake or bar, colloquially called a "pill"
Computing
* Tablet computer, a mobile computer that is primarily operated by touching the s ...
, or smartphone. A user can give input or control the information processing system through simple or
multi-touch
In computing, multi-touch is technology that enables a surface (a touchpad or touchscreen) to recognize the presence of more than one somatosensory system, point of contact with the surface at the same time. The origins of multitouch began at CER ...
gestures by touching the screen with a special
stylus
A stylus (plural styli or styluses) is a writing utensil or a small tool for some other form of marking or shaping, for example, in pottery. It can also be a computer accessory that is used to assist in navigating or providing more precision w ...
or one or more fingers. Some touchscreens use ordinary or specially coated gloves to work while others may only work using a special stylus or pen. The user can use the touchscreen to react to what is displayed and, if the software allows, to control how it is displayed; for example,
zooming to increase the text size.
The touchscreen enables the user to interact directly with what is displayed, rather than using a
mouse
A mouse ( : mice) is a small rodent. Characteristically, mice are known to have a pointed snout, small rounded ears, a body-length scaly tail, and a high breeding rate. The best known mouse species is the common house mouse (''Mus musculus' ...
,
touchpad
A touchpad or trackpad is a pointing device featuring a tactile sensor, a specialized surface that can translate the motion and position of a user's fingers to a relative position on the operating system that is made output to the screen. Touchp ...
, or other such devices (other than a stylus, which is optional for most modern touchscreens).
Touchscreens are common in devices such as
game consoles
A video game console is an electronic device that outputs a video signal or image to display a video game that can be played with a game controller. These may be home consoles, which are generally placed in a permanent location connected to a t ...
,
personal computer
A personal computer (PC) is a multi-purpose microcomputer whose size, capabilities, and price make it feasible for individual use. Personal computers are intended to be operated directly by an end user, rather than by a computer expert or tec ...
s,
electronic voting machine
An electronic voting machine is a voting machine based on electronics.
Two main technologies exist: '' optical scanning'' and '' direct recording'' (DRE).
Optical scanning
In an optical scan voting system, or marksense, each voter's choices ...
s, and
point-of-sale
The point of sale (POS) or point of purchase (POP) is the time and place at which a retail transaction is completed. At the point of sale, the merchant calculates the amount owed by the customer, indicates that amount, may prepare an invoice f ...
(POS) systems. They can also be attached to computers or, as terminals, to networks. They play a prominent role in the design of digital appliances such as
personal digital assistant
A personal digital assistant (PDA), also known as a handheld PC, is a variety mobile device which functions as a personal information manager. PDAs have been mostly displaced by the widespread adoption of highly capable smartphones, in partic ...
s (PDAs) and some
e-reader
An e-reader, also called an e-book reader or e-book device, is a mobile electronic device that is designed primarily for the purpose of reading digital e-books and periodicals.
Any device that can display text on a screen may act as an e-read ...
s. Touchscreens are also important in educational settings such as classrooms or on college campuses.
The popularity of smartphones, tablets, and many types of
information appliance
An information appliance (IA) is an appliance that is designed to easily perform a specific electronic function such as playing music, photography, or editing text.
Typical examples are smartphones and personal digital assistants (PDAs). Inf ...
s is driving the demand and acceptance of common touchscreens for portable and functional electronics. Touchscreens are found in the medical field,
heavy industry
Heavy industry is an industry that involves one or more characteristics such as large and heavy products; large and heavy equipment and facilities (such as heavy equipment, large machine tools, huge buildings and large-scale infrastructure); o ...
,
automated teller machine
An automated teller machine (ATM) or cash machine (in British English) is an electronic telecommunications device that enables customers of financial institutions to perform financial transactions, such as cash withdrawals, deposits, fun ...
s (ATMs), and kiosks such as museum displays or
room automation
Building automation (BAS), also known as building management system (BMS) or building energy management system (BEMS), is the automatic centralized control of a building's HVAC, HVAC (heating, ventilation and air conditioning), electrical, ligh ...
, where
keyboard
Keyboard may refer to:
Text input
* Keyboard, part of a typewriter
* Computer keyboard
** Keyboard layout, the software control of computer keyboards and their mapping
** Keyboard technology, computer keyboard hardware and firmware
Music
* Musi ...
and
mouse
A mouse ( : mice) is a small rodent. Characteristically, mice are known to have a pointed snout, small rounded ears, a body-length scaly tail, and a high breeding rate. The best known mouse species is the common house mouse (''Mus musculus' ...
systems do not allow a suitably intuitive, rapid, or accurate interaction by the user with the display's content.
Historically, the touchscreen sensor and its accompanying controller-based
firmware
In computing, firmware is a specific class of computer software that provides the low-level control for a device's specific hardware. Firmware, such as the BIOS of a personal computer, may contain basic functions of a device, and may provide h ...
have been made available by a wide array of after-market
system integrator
A systems integrator (or system integrator) is a person or company that specializes in bringing together component subsystems into a whole and ensuring that those subsystems function together, a practice known as system integration. They also sol ...
s, and not by display, chip, or
motherboard
A motherboard (also called mainboard, main circuit board, mb, mboard, backplane board, base board, system board, logic board (only in Apple computers) or mobo) is the main printed circuit board (PCB) in general-purpose computers and other expand ...
manufacturers. Display manufacturers and chip manufacturers have acknowledged the trend toward acceptance of touchscreens as a
user interface
In the industrial design field of human–computer interaction, a user interface (UI) is the space where interactions between humans and machines occur. The goal of this interaction is to allow effective operation and control of the machine f ...
component and have begun to integrate touchscreens into the fundamental design of their products.
History
![CERN-Stumpe Capacitance Touchscreen](https://upload.wikimedia.org/wikipedia/commons/5/5e/CERN-Stumpe_Capacitance_Touchscreen.jpg)
One predecessor of the modern touch screen includes stylus based systems. In 1946, a patent was filed by
Philco Company for a stylus designed for sports telecasting which, when placed against an intermediate
cathode ray tube display
A cathode-ray tube (CRT) is a vacuum tube containing one or more electron guns, which emit electron beams that are manipulated to display images on a phosphorescent screen. The images may represent electrical waveforms (oscilloscope), pictur ...
(CRT) would amplify and add to the original signal. Effectively, this was used for temporarily drawing arrows or circles onto a live television broadcast, as described in . Later inventions built upon this system to free telewriting styli from their mechanical bindings. By transcribing what a user draws onto a computer, it could be saved for future use. See .
The first version of a touchscreen which operated independently of the light produced from the screen was patented by
AT&T Corporation
AT&T Corporation, originally the American Telephone and Telegraph Company, is the subsidiary of AT&T Inc. that provides voice, video, data, and Internet telecommunications and professional services to businesses, consumers, and government agen ...
. This touchscreen utilized a matrix of collimated lights shining orthogonally across the touch surface. When a beam is interrupted by a stylus, the
photodetector
Photodetectors, also called photosensors, are sensors of light or other electromagnetic radiation. There is a wide variety of photodetectors which may be classified by mechanism of detection, such as Photoelectric effect, photoelectric or photoc ...
s which no longer are receiving a signal can be used to determine where the interruption is. Later iterations of matrix based touchscreens built upon this by adding more emitters and detectors to improve resolution, pulsing emitters to improve optical
signal to noise ratio
In signal processing, a signal is a function that conveys information about a phenomenon. Any quantity that can vary over space or time can be used as a signal to share messages between observers. The ''IEEE Transactions on Signal Processing'' ...
, and a nonorthogonal matrix to remove shadow readings when using multi-touch.
The first finger driven touch screen was developed by Eric Johnson, of the
Royal Radar Establishment
The Royal Radar Establishment was a research centre in Malvern, Worcestershire in the United Kingdom. It was formed in 1953 as the Radar Research Establishment by the merger of the Air Ministry's Telecommunications Research Establishment (TRE) a ...
located in
Malvern
Malvern or Malverne may refer to:
Places Australia
* Malvern, South Australia, a suburb of Adelaide
* Malvern, Victoria, a suburb of Melbourne
* City of Malvern, a former local government area near Melbourne
* Electoral district of Malvern, an e ...
, England, who described his work on capacitive touchscreens in a short article published in 1965
and then more fully—with photographs and diagrams—in an article published in 1967. The application of touch technology for air traffic control was described in an article published in 1968.
Frank Beck and
Bent Stumpe
Bent Stumpe (born 12 September 1938, Copenhagen, Denmark) is a Danish electronic engineer who spent most of his career at the international research laboratory CERN, Geneva, Switzerland. Stumpe built in 1972, following an idea launched by Frank ...
, engineers from
CERN
The European Organization for Nuclear Research, known as CERN (; ; ), is an intergovernmental organization that operates the largest particle physics laboratory in the world. Established in 1954, it is based in a northwestern suburb of Gene ...
(European Organization for Nuclear Research), developed a transparent touchscreen in the early 1970s,
based on Stumpe's work at a television factory in the early 1960s. Then manufactured by CERN, and shortly after by industry partners, it was put to use in 1973.
In the mid-1960s, another precursor of touchscreens, an ultrasonic-curtain-based pointing device in front of a terminal display, had been developed by a team around at
Telefunken
Telefunken was a German radio and television apparatus company, founded in Berlin in 1903, as a joint venture of Siemens & Halske and the ''Allgemeine Elektrizitäts-Gesellschaft'' (AEG) ('General electricity company').
The name "Telefunken" app ...
for an air traffic control system.
In 1970, this evolved into a device named "Touchinput-" ("touch input facility") for the SIG 50 terminal utilizing a conductively coated glass screen in front of the display.
This was patented in 1971 and the patent was granted a couple of years later.
The same team had already invented and marketed the mouse RKS 100-86 for the SIG 100-86 a couple of years earlier.
In 1972, a group at the
University of Illinois
The University of Illinois Urbana-Champaign (U of I, Illinois, University of Illinois, or UIUC) is a public land-grant research university in Illinois in the twin cities of Champaign and Urbana. It is the flagship institution of the University ...
filed for a patent on an optical touchscreen that became a standard part of the
Magnavox
Magnavox (Latin for "great voice", stylized as MAGNAVOX) is an American electronics company that since 1974 has been a subsidiary of the Dutch electronics corporation Philips.
The predecessor to Magnavox was founded in 1911 by Edwin Pridham and ...
Plato IV Student Terminal and thousands were built for this purpose. These touchscreens had a crossed array of 16×16
infrared
Infrared (IR), sometimes called infrared light, is electromagnetic radiation (EMR) with wavelengths longer than those of visible light. It is therefore invisible to the human eye. IR is generally understood to encompass wavelengths from around ...
position sensors, each composed of an
LED
A light-emitting diode (LED) is a semiconductor Electronics, device that Light#Light sources, emits light when Electric current, current flows through it. Electrons in the semiconductor recombine with electron holes, releasing energy i ...
on one edge of the screen and a matched
phototransistor
A photodiode is a light-sensitive semiconductor diode. It produces current when it absorbs photons.
The package of a photodiode allows light (or infrared or ultraviolet radiation, or X-rays) to reach the sensitive part of the device. The packa ...
on the other edge, all mounted in front of a monochrome
plasma display
A plasma display panel (PDP) is a type of flat panel display that uses small cells containing plasma: ionized gas that responds to electric fields. Plasma televisions were the first large (over 32 inches diagonal) flat panel displays to be release ...
panel. This arrangement could sense any fingertip-sized opaque object in close proximity to the screen. A similar touchscreen was used on the
HP-150 starting in 1983. The HP 150 was one of the world's earliest commercial touchscreen computers. HP mounted their
infrared
Infrared (IR), sometimes called infrared light, is electromagnetic radiation (EMR) with wavelengths longer than those of visible light. It is therefore invisible to the human eye. IR is generally understood to encompass wavelengths from around ...
transmitter
In electronics and telecommunications, a radio transmitter or just transmitter is an electronic device which produces radio waves with an antenna (radio), antenna. The transmitter itself generates a radio frequency alternating current, which i ...
s and receivers around the bezel of a 9-inch
Sony
, commonly stylized as SONY, is a Japanese multinational conglomerate corporation headquartered in Minato, Tokyo, Japan. As a major technology company, it operates as one of the world's largest manufacturers of consumer and professional ...
cathode ray tube (CRT).
In 1977, an American company, Elographics – in partnership with Siemens – began work on developing a transparent implementation of an existing opaque touchpad technology, U.S. patent 3,911,215, October 7, 1975, which had been developed by Elographics' founder
George Samuel Hurst.
The resulting resistive technology touch screen was first shown on the
World's Fair
A world's fair, also known as a universal exhibition or an expo, is a large international exhibition designed to showcase the achievements of nations. These exhibitions vary in character and are held in different parts of the world at a specif ...
at
Knoxville
Knoxville is a city in and the county seat of Knox County in the U.S. state of Tennessee. As of the 2020 United States census, Knoxville's population was 190,740, making it the largest city in the East Tennessee Grand Division and the state's ...
in 1982.
In 1984,
Fujitsu
is a Japanese multinational information and communications technology equipment and services corporation, established in 1935 and headquartered in Tokyo. Fujitsu is the world's sixth-largest IT services provider by annual revenue, and the la ...
released a touch pad for the
Micro 16 to accommodate the complexity of
kanji
are the logographic Chinese characters taken from the Chinese family of scripts, Chinese script and used in the writing of Japanese language, Japanese. They were made a major part of the Japanese writing system during the time of Old Japanese ...
characters, which were stored as
tiled graphics. In 1985,
Sega
is a Japanese multinational corporation, multinational video game and entertainment company headquartered in Shinagawa, Tokyo. Its international branches, Sega of America and Sega Europe, are headquartered in Irvine, California and London, r ...
released the Terebi Oekaki, also known as the Sega Graphic Board, for the
SG-1000
The is a home video game console manufactured by Sega. It was Sega's first entry into the home video game hardware business. Developed in response to a downturn in arcades starting in 1982, the SG-1000 was created on the advice of Hayao Nakay ...
video game console
A video game console is an electronic device that Input/output, outputs a video signal or image to display a video game that can be played with a game controller. These may be home video game console, home consoles, which are generally placed i ...
and
SC-3000
The is a home video game console manufactured by Sega. It was Sega's first entry into the home video game hardware business. Developed in response to a downturn in arcades starting in 1982, the SG-1000 was created on the advice of Hayao Nakay ...
home computer. It consisted of a plastic pen and a plastic board with a transparent window where pen presses are detected. It was used primarily with a drawing software application. A graphic touch tablet was released for the Sega AI computer in 1986.
Touch-sensitive
control-display units (CDUs) were evaluated for commercial aircraft flight decks in the early 1980s. Initial research showed that a touch interface would reduce pilot workload as the crew could then select waypoints, functions and actions, rather than be "head down" typing latitudes, longitudes, and waypoint codes on a keyboard. An effective integration of this technology was aimed at helping flight crews maintain a high level of
situational awareness
Situational awareness or situation awareness (SA) is the perception of environmental elements and events with respect to time or space, the comprehension of their meaning, and the projection of their future status. An alternative definition is tha ...
of all major aspects of the vehicle operations including the flight path, the functioning of various aircraft systems, and moment-to-moment human interactions.
In the early 1980s,
General Motors
The General Motors Company (GM) is an American Multinational corporation, multinational Automotive industry, automotive manufacturing company headquartered in Detroit, Michigan, United States. It is the largest automaker in the United States and ...
tasked its
Delco Electronics
Delco Electronics Corporation was the automotive electronics design and manufacturing subsidiary of General Motors based in Kokomo, Indiana, that manufactured ''Delco'' Automobile radios and other electric products found in GM cars. In 1972, Gene ...
division with a project aimed at replacing an automobile's non-essential functions (i.e. other than
throttle
A throttle is the mechanism by which fluid flow is managed by constriction or obstruction.
An engine's power can be increased or decreased by the restriction of inlet gases (by the use of a throttle), but usually decreased. The term ''throttle'' ...
,
transmission
Transmission may refer to:
Medicine, science and technology
* Power transmission
** Electric power transmission
** Propulsion transmission, technology allowing controlled application of power
*** Automatic transmission
*** Manual transmission
*** ...
,
braking
A brake is a mechanical device that inhibits motion by absorbing energy from a moving system. It is used for slowing or stopping a moving vehicle, wheel, axle, or to prevent its motion, most often accomplished by means of friction.
Background ...
, and
steering
Steering is a system of components, linkages, and other parts that allows a driver to control the direction of the vehicle.
Introduction
The most conventional steering arrangement allows a driver to turn the front wheels of a vehicle using ...
) from mechanical or electro-mechanical systems with
solid state alternatives wherever possible. The finished device was dubbed the ECC for "Electronic Control Center", a
digital computer
A computer is a machine that can be programmed to carry out sequences of arithmetic or logical operations ( computation) automatically. Modern digital electronic computers can perform generic sets of operations known as programs. These pro ...
and
software
Software is a set of computer programs and associated documentation and data. This is in contrast to hardware, from which the system is built and which actually performs the work.
At the lowest programming level, executable code consists ...
control system hardwired to various
peripheral
A peripheral or peripheral device is an auxiliary device used to put information into and get information out of a computer. The term ''peripheral device'' refers to all hardware components that are attached to a computer and are controlled by the ...
sensors
A sensor is a device that produces an output signal for the purpose of sensing a physical phenomenon.
In the broadest definition, a sensor is a device, module, machine, or subsystem that detects events or changes in its environment and sends ...
,
servos
In control engineering a servomechanism, usually shortened to servo, is an automatic device that uses error-sensing negative feedback to correct the action of a mechanism. On displacement-controlled applications, it usually includes a built-in ...
,
solenoids
upright=1.20, An illustration of a solenoid
upright=1.20, Magnetic field created by a seven-loop solenoid (cross-sectional view) described using field lines
A solenoid () is a type of electromagnet formed by a helix, helical coil of wire whose ...
,
antenna
Antenna ( antennas or antennae) may refer to:
Science and engineering
* Antenna (radio), also known as an aerial, a transducer designed to transmit or receive electromagnetic (e.g., TV or radio) waves
* Antennae Galaxies, the name of two collid ...
and a
monochrome
A monochrome or monochromatic image, object or palette is composed of one color (or values of one color). Images using only shades of grey are called grayscale (typically digital) or black-and-white (typically analog). In physics, monochrom ...
CRT touchscreen that functioned both as display and sole method of input. The ECC replaced the traditional mechanical
stereo
Stereophonic sound, or more commonly stereo, is a method of sound reproduction that recreates a multi-directional, 3-dimensional audible perspective. This is usually achieved by using two independent audio channels through a configuration ...
, fan, heater and
air conditioner
Air conditioning, often abbreviated as A/C or AC, is the process of removing heat from an enclosed space to achieve a more comfortable interior environment (sometimes referred to as 'comfort cooling') and in some cases also strictly controlling ...
controls and displays, and was capable of providing very detailed and specific information about the vehicle's cumulative and current operating status in
real time
Real-time or real time describes various operations in computing or other processes that must guarantee response times within a specified time (deadline), usually a relatively short time. A real-time process is generally one that happens in defined ...
. The ECC was standard equipment on the 1985–1989
Buick Riviera
The Buick Riviera is a personal luxury car that was marketed by Buick from 1963 to 1999, with the exception of the 1994 model year.
As General Motors' first entry into the personal luxury car market segment, the Riviera was highly praised by au ...
and later the 1988–1989
Buick Reatta
The Buick Reatta is a low-volume transverse front-engine, front-wheel drive, two-door, two-seater grand tourer manufactured and marketed by Buick as a coupe (1988–1991) and convertible (1990-1991) — both featuring a 3.8 liter V6 engine an ...
, but was unpopular with consumers—partly due to the
technophobia
Technophobia (from Greek τέχνη ''technē'', "art, skill, craft" and φόβος ''phobos'', "fear"), also known as technofear, is the fear or dislike of advanced technology or complex devices, especially computers. Although there are numerou ...
of some traditional
Buick
Buick () is a division of the American automobile manufacturer General Motors (GM). Started by automotive pioneer David Dunbar Buick in 1899, it was among the first American marques of automobiles, and was the company that established General ...
customers, but mostly because of costly technical problems suffered by the ECC's touchscreen which would render climate control or stereo operation impossible.
Multi-touch
In computing, multi-touch is technology that enables a surface (a touchpad or touchscreen) to recognize the presence of more than one somatosensory system, point of contact with the surface at the same time. The origins of multitouch began at CER ...
technology began in 1982, when the
University of Toronto
The University of Toronto (UToronto or U of T) is a public research university in Toronto, Ontario, Canada, located on the grounds that surround Queen's Park. It was founded by royal charter in 1827 as King's College, the first institution ...
's Input Research Group developed the first human-input multi-touch system, using a frosted-glass panel with a camera placed behind the glass. In 1985, the University of Toronto group, including Bill Buxton, developed a multi-touch tablet that used capacitance rather than bulky camera-based optical sensing systems (see
History of multi-touch).
The first commercially available graphical
point-of-sale
The point of sale (POS) or point of purchase (POP) is the time and place at which a retail transaction is completed. At the point of sale, the merchant calculates the amount owed by the customer, indicates that amount, may prepare an invoice f ...
(POS) software was demonstrated on the 16-bit
Atari 520ST
The Atari ST is a line of personal computers from Atari Corporation and the successor to the Atari 8-bit family. The initial model, the Atari 520ST, had limited release in April–June 1985 and was widely available in July. It was the first per ...
color computer. It featured a color touchscreen widget-driven interface. The ViewTouch POS software was first shown by its developer, Gene Mosher, at the Atari Computer demonstration area of the Fall
COMDEX
COMDEX (an abbreviation of COMputer Dealers' EXhibition) was a computer expo trade show held in the Las Vegas Valley of Nevada, United States, each November from 1979 to 2003. It was one of the largest computer trade shows in the world, usually ...
expo in 1986.
In 1987, Casio launched the
Casio PB-1000
The Casio PB-1000 is a handheld computer released by Casio in 1987. It featured a touchscreen display which consisted of 16 keys built into the screen, arranged in fixed positions on a four by four matrix.
The computer itself included 8Kb of R ...
pocket computer with a touchscreen consisting of a 4×4 matrix, resulting in 16 touch areas in its small LCD graphic screen.
Touchscreens had a bad reputation of being imprecise until 1988. Most user-interface books would state that touchscreen selections were limited to targets larger than the average finger. At the time, selections were done in such a way that a target was selected as soon as the finger came over it, and the corresponding action was performed immediately. Errors were common, due to parallax or calibration problems, leading to user frustration. "Lift-off strategy"
was introduced by researchers at the
University of Maryland Human–Computer Interaction Lab
The Human–Computer Interaction Lab (HCIL) at the University of Maryland, College Park is an academic research center specializing in the field of human-computer interaction (HCI). Founded in 1983 by Ben Shneiderman, it is one of the oldest HCI ...
(HCIL). As users touch the screen, feedback is provided as to what will be selected: users can adjust the position of the finger, and the action takes place only when the finger is lifted off the screen. This allowed the selection of small targets, down to a single pixel on a 640×480
Video Graphics Array
Video Graphics Array (VGA) is a video display controller and accompanying de facto graphics standard, first introduced with the IBM PS/2 line of computers in 1987, which became ubiquitous in the PC industry within three years. The term can now ...
(VGA) screen (a standard of that time).
Sears et al. (1990)
gave a review of academic research on single and multi-touch
human–computer interaction
Human–computer interaction (HCI) is research in the design and the use of computer technology, which focuses on the interfaces between people (users) and computers. HCI researchers observe the ways humans interact with computers and design tec ...
of the time, describing gestures such as rotating knobs, adjusting sliders, and swiping the screen to activate a switch (or a U-shaped gesture for a toggle switch). The HCIL team developed and studied small touchscreen keyboards (including a study that showed users could type at 25 on a touchscreen keyboard), aiding their introduction on mobile devices. They also designed and implemented multi-touch gestures such as selecting a range of a line, connecting objects, and a "tap-click" gesture to select while maintaining location with another finger.
In 1990, HCIL demonstrated a touchscreen slider,
which was later cited as prior art in the
lock screen
A lock screen is a computer user interface element used by various operating systems. They regulate immediate access to a device by requiring the user to perform a certain action in order to receive access, such as entering a password, using a cert ...
patent litigation between Apple and other touchscreen mobile phone vendors (in relation to ).
In 1991–1992, the
Sun
The Sun is the star at the center of the Solar System. It is a nearly perfect ball of hot plasma, heated to incandescence by nuclear fusion reactions in its core. The Sun radiates this energy mainly as light, ultraviolet, and infrared radi ...
Star7 prototype
PDA
PDA may refer to:
Science and technology
* Patron-driven acquisition, a mechanism for libraries to purchase books
*Personal digital assistant, a mobile device
* Photodiode array, a type of detector
* Polydiacetylenes, a family of conducting poly ...
implemented a touchscreen with
inertial scrolling. In 1993, IBM released the
IBM Simon
The IBM Simon Personal Communicator (simply known as IBM Simon) is a handheld, touchscreen PDA designed by International Business Machines (IBM), and manufactured by Mitsubishi Electric. Although the term "smartphone" was not coined until 199 ...
the first touchscreen phone.
An early attempt at a
handheld game console
A handheld game console, or simply handheld console, is a small, portable self-contained video game console with a built-in screen, game controls and speakers. Handheld game consoles are smaller than home video game consoles and contain the cons ...
with touchscreen
controls was
Sega
is a Japanese multinational corporation, multinational video game and entertainment company headquartered in Shinagawa, Tokyo. Its international branches, Sega of America and Sega Europe, are headquartered in Irvine, California and London, r ...
's intended successor to the
Game Gear
The is an 8-bit fourth generation handheld game console released by Sega on October 6, 1990, in Japan, in April 1991 throughout North America and Europe, and during 1992 in Australia. The Game Gear primarily competed with Nintendo's Game Boy, ...
, though the device was ultimately shelved and never released due to the expensive cost of touchscreen technology in the early 1990s.
The first
mobile phone
A mobile phone, cellular phone, cell phone, cellphone, handphone, hand phone or pocket phone, sometimes shortened to simply mobile, cell, or just phone, is a portable telephone that can make and receive calls over a radio frequency link whil ...
with a capacitive touchscreen was
LG Prada
The LG KE850, also known as the LG Prada, is a touchscreen mobile phone made by LG Electronics. It was first announced on December 12, 2006 and was created in collaboration with Italian luxury designer Prada. It was made official in a press rele ...
released in May 2007 (which was before the first
iPhone).
By 2009, touchscreen-enabled mobile phones were becoming trendy and quickly gaining popularity in both basic and advanced devices. In Q4 2009 for the first time, a majority of smartphones (i.e. not all mobile phones) shipped with touchscreens over non-touch.
Touchscreens would not be popularly used for video games until the release of the
Nintendo DS
The is a handheld game console produced by Nintendo, released globally across 2004 and 2005. The DS, an initialism for "Developers' System" or "Dual Screen", introduced distinctive new features to handheld games: two LCD screens working in tan ...
in 2004. Until recently, most consumer touchscreens could only sense one point of contact at a time, and few have had the capability to sense how hard one is touching. This has changed with the commercialization of multi-touch technology, and the
Apple Watch
Apple Watch is a line of smartwatches produced by Apple Inc. It incorporates fitness tracking, health-oriented capabilities, and wireless telecommunication, and integrates with iOS and other Apple products and services. The Apple Watch was rel ...
being released with a force-sensitive display in April 2015.
In 2007, 93% of touchscreens shipped were resistive and only 4% were projected capacitance. In 2013, 3% of touchscreens shipped were resistive and 90% were projected capacitance.
Technologies
There is a variety of touchscreen technologies with different methods of sensing touch.
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Resistive
A resistive
The electrical resistance of an object is a measure of its opposition to the flow of electric current. Its reciprocal quantity is , measuring the ease with which an electric current passes. Electrical resistance shares some conceptual parallels ...
touchscreen panel comprises several thin layers, the most important of which are two transparent electrically resistive layers facing each other with a thin gap between. The top layer (that which is touched) has a coating on the underside surface; just beneath it is a similar resistive layer on top of its substrate. One layer has conductive connections along its sides, the other along top and bottom. A voltage is applied to one layer and sensed by the other. When an object, such as a fingertip or stylus tip, presses down onto the outer surface, the two layers touch to become connected at that point. The panel then behaves as a pair of voltage divider
In electronics, a voltage divider (also known as a potential divider) is a passive linear circuit that produces an output voltage (''V''out) that is a fraction of its input voltage (''V''in). Voltage division is the result of distributing the in ...
s, one axis at a time. By rapidly switching between each layer, the position of pressure on the screen can be detected.
Resistive touch is used in restaurants, factories and hospitals due to its high tolerance for liquids and contaminants. A major benefit of resistive-touch technology is its low cost. Additionally, as only sufficient pressure is necessary for the touch to be sensed, they may be used with gloves on, or by using anything rigid as a finger substitute. Disadvantages include the need to press down, and a risk of damage by sharp objects. Resistive touchscreens also suffer from poorer contrast, due to having additional reflections (i.e. glare) from the layers of material placed over the screen. This is the type of touchscreen that was used by Nintendo in the DS family, the 3DS family, and the Wii U GamePad
The Wii U GamePad is the standard game controller for Nintendo's Wii U home video game console. Incorporating traits from tablet computers, the GamePad has traditional input methods (such as buttons, dual analog sticks, and a D-pad), touchscreen ...
.
Surface acoustic wave
Surface acoustic wave (SAW) technology uses ultrasonic
Ultrasound is sound waves with frequencies higher than the upper audible limit of human hearing. Ultrasound is not different from "normal" (audible) sound in its physical properties, except that humans cannot hear it. This limit varies fr ...
waves that pass over the touchscreen panel. When the panel is touched, a portion of the wave is absorbed. The change in ultrasonic waves is processed by the controller
Controller may refer to:
Occupations
* Controller or financial controller, or in government accounting comptroller, a senior accounting position
* Controller, someone who performs agent handling in espionage
* Air traffic controller, a person ...
to determine the position of the touch event. Surface acoustic wave touchscreen panels can be damaged by outside elements. Contaminants on the surface can also interfere with the functionality of the touchscreen.
SAW devices have a wide range of applications, including delay lines, filters, correlators and DC to DC converter
A DC-to-DC converter is an electronic circuit or electromechanical device that converts a source of direct current (DC) from one voltage level to another. It is a type of electric power converter. Power levels range from very low (small batteries) ...
s.
Capacitive
A capacitive touchscreen panel consists of an insulator, such as glass
Glass is a non-crystalline, often transparent, amorphous solid that has widespread practical, technological, and decorative use in, for example, window panes, tableware, and optics. Glass is most often formed by rapid cooling (quenching) of ...
, coated with a transparent conductor, such as indium tin oxide Indium tin oxide (ITO) is a ternary composition of indium, tin and oxygen in varying proportions. Depending on the oxygen content, it can be described as either a ceramic or an alloy. Indium tin oxide is typically encountered as an oxygen-saturated ...
(ITO). As the human body is also an electrical conductor, touching the surface of the screen results in a distortion of the screen's electrostatic
Electrostatics is a branch of physics that studies electric charges at rest (static electricity).
Since classical times, it has been known that some materials, such as amber, attract lightweight particles after rubbing. The Greek word for amber ...
field, measurable as a change in capacitance
Capacitance is the capability of a material object or device to store electric charge. It is measured by the change in charge in response to a difference in electric potential, expressed as the ratio of those quantities. Commonly recognized are ...
. Different technologies may be used to determine the location of the touch. The location is then sent to the controller for processing. Touchscreens that use silver instead of ITO exist, as ITO causes several environmental problems due to the use of indium. The controller is typically a complementary metal-oxide-semiconductor
Complementary metal–oxide–semiconductor (CMOS, pronounced "sea-moss", ) is a type of metal–oxide–semiconductor field-effect transistor (MOSFET) fabrication process that uses complementary and symmetrical pairs of p-type and n-type MOSFE ...
(CMOS) application-specific integrated circuit
An application-specific integrated circuit (ASIC ) is an integrated circuit (IC) chip customized for a particular use, rather than intended for general-purpose use, such as a chip designed to run in a digital voice recorder or a high-efficie ...
(ASIC) chip, which in turn usually sends the signals to a CMOS digital signal processor
A digital signal processor (DSP) is a specialized microprocessor chip, with its architecture optimized for the operational needs of digital signal processing. DSPs are fabricated on MOS integrated circuit chips. They are widely used in audio si ...
(DSP) for processing.
Unlike a resistive touchscreen
In electrical engineering, a resistive touchscreen is a touch-sensitive computer display composed of two flexible sheets coated with a resistive material and separated by an air gap or microdots.
Description and operation
There are two differ ...
, some capacitive touchscreens cannot be used to detect a finger through electrically insulating material, such as gloves. This disadvantage especially affects usability in consumer electronics, such as touch tablet PCs and capacitive smartphones in cold weather when people may be wearing gloves. It can be overcome with a special capacitive stylus, or a special-application glove with an embroidered patch of conductive thread allowing electrical contact with the user's fingertip.
A low-quality switching-mode power supply unit with an accordingly unstable, noisy voltage
Voltage, also known as electric pressure, electric tension, or (electric) potential difference, is the difference in electric potential between two points. In a static electric field, it corresponds to the work needed per unit of charge to m ...
may temporarily interfere with the precision, accuracy and sensitivity of capacitive touch screens.
Some capacitive display manufacturers continue to develop thinner and more accurate touchscreens. Those for mobile device
A mobile device (or handheld computer) is a computer small enough to hold and operate in the hand. Mobile devices typically have a flat LCD or OLED screen, a touchscreen interface, and digital or physical buttons. They may also have a physical ...
s are now being produced with 'in-cell' technology, such as in Samsung's Super AMOLED
AMOLED (active-matrix organic light-emitting diode, ) is a type of OLED display device technology. OLED describes a specific type of thin-film-display technology in which organic compounds form the electroluminescent material, and active matrix ...
screens, that eliminates a layer by building the capacitors inside the display itself. This type of touchscreen reduces the visible distance between the user's finger and what the user is touching on the screen, reducing the thickness and weight of the display, which is desirable in smartphone
A smartphone is a portable computer device that combines mobile telephone and computing functions into one unit. They are distinguished from feature phones by their stronger hardware capabilities and extensive mobile operating systems, whic ...
s.
A simple parallel-plate capacitor has two conductors separated by a dielectric layer. Most of the energy in this system is concentrated directly between the plates. Some of the energy spills over into the area outside the plates, and the electric field lines associated with this effect are called fringing fields. Part of the challenge of making a practical capacitive sensor is to design a set of printed circuit traces which direct fringing fields into an active sensing area accessible to a user. A parallel-plate capacitor is not a good choice for such a sensor pattern. Placing a finger near fringing electric fields adds conductive surface area to the capacitive system. The additional charge storage capacity added by the finger is known as finger capacitance, or CF. The capacitance of the sensor without a finger present is known as parasitic capacitance, or CP.
Surface capacitance
In this basic technology, only one side of the insulator is coated with a conductive layer. A small voltage is applied to the layer, resulting in a uniform electrostatic field. When a conductor, such as a human finger, touches the uncoated surface, a capacitor is dynamically formed. The sensor's controller can determine the location of the touch indirectly from the change in the capacitance as measured from the four corners of the panel. As it has no moving parts, it is moderately durable but has limited resolution, is prone to false signals from parasitic capacitive coupling
Capacitive coupling is the transfer of energy within an electrical network or between distant networks by means of displacement current between circuit(s) nodes, induced by the electric field. This coupling can have an intentional or accidental ...
, and needs calibration
In measurement technology and metrology, calibration is the comparison of measurement values delivered by a device under test with those of a calibration standard of known accuracy. Such a standard could be another measurement device of know ...
during manufacture. It is therefore most often used in simple applications such as industrial controls and kiosks
Historically, a kiosk () was a small garden pavilion open on some or all sides common in Persia, the Indian subcontinent, and in the Ottoman Empire from the 13th century onward. Today, several examples of this type of kiosk still exist in an ...
.
Although some standard capacitance detection methods are projective, in the sense that they can be used to detect a finger through a non-conductive surface, they are very sensitive to fluctuations in temperature, which expand or contract the sensing plates, causing fluctuations in the capacitance of these plates. These fluctuations result in a lot of background noise, so a strong finger signal is required for accurate detection. This limits applications to those where the finger directly touches the sensing element or is sensed through a relatively thin non-conductive surface.
Projected capacitance
Projected capacitive touch (PCT; also PCAP) technology is a variant of capacitive touch technology but where sensitivity to touch, accuracy, resolution and speed of touch have been greatly improved by the use of a simple form of
"Artificial Intelligence". This intelligent processing enables finger sensing to be projected, accurately and reliably, through very thick glass and even double glazing.
Some modern PCT touch screens are composed of thousands of discrete keys, but most PCT touch screens are made of an x/y matrix of rows and columns of conductive material, layered on sheets of glass.
This can be done either by etching
Etching is traditionally the process of using strong acid or mordant to cut into the unprotected parts of a metal surface to create a design in intaglio (incised) in the metal. In modern manufacturing, other chemicals may be used on other types ...
a single conductive layer to form a grid pattern of electrode
An electrode is an electrical conductor used to make contact with a nonmetallic part of a circuit (e.g. a semiconductor, an electrolyte, a vacuum or air). Electrodes are essential parts of batteries that can consist of a variety of materials de ...
s, by etching two separate, perpendicular layers of conductive material with parallel lines or tracks to form a grid, or by forming an x/y grid of fine, insulation coated wires in a single layer . The number of fingers that can be detected simultaneously is determined by the number of cross-over points (x * y) . However, the number of cross-over points can be almost doubled by using a diagonal lattice layout, where, instead of x elements only ever crossing y elements, each conductive element crosses every other element .
The conductive layer is often transparent, being made of Indium tin oxide Indium tin oxide (ITO) is a ternary composition of indium, tin and oxygen in varying proportions. Depending on the oxygen content, it can be described as either a ceramic or an alloy. Indium tin oxide is typically encountered as an oxygen-saturated ...
(ITO), a transparent electrical conductor.
In some designs, voltage applied to this grid creates a uniform electrostatic field, which can be measured. When a conductive object, such as a finger, comes into contact with a PCT panel, it distorts the local electrostatic field at that point. This is measurable as a change in capacitance. If a finger bridges the gap between two of the "tracks", the charge field is further interrupted and detected by the controller. The capacitance can be changed and measured at every individual point on the grid. This system is able to accurately track touches.
Due to the top layer of a PCT being glass, it is sturdier than less-expensive resistive touch technology.
Unlike traditional capacitive touch technology, it is possible for a PCT system to sense a passive stylus or gloved finger. However, moisture on the surface of the panel, high humidity, or collected dust can interfere with performance.
These environmental factors, however, are not a problem with 'fine wire' based touchscreens due to the fact that wire based touchscreens have a much lower 'parasitic' capacitance, and there is greater distance between neighbouring conductors.
There are two types of PCT: mutual capacitance and self-capacitance.
Mutual capacitance
This is a common PCT approach, which makes use of the fact that most conductive objects are able to hold a charge if they are very close together. In mutual capacitive sensors, a capacitor is inherently formed by the row trace and column trace at each intersection of the grid. A 16×14 array, for example, would have 224 independent capacitors. A voltage is applied to the rows or columns. Bringing a finger or conductive stylus close to the surface of the sensor changes the local electrostatic field, which in turn reduces the mutual capacitance. The capacitance change at every individual point on the grid can be measured to accurately determine the touch location by measuring the voltage in the other axis. Mutual capacitance allows multi-touch operation where multiple fingers, palms or styli can be accurately tracked at the same time.
Self-capacitance
Self-capacitance sensors can have the same X-Y grid as mutual capacitance sensors, but the columns and rows operate independently. With self-capacitance, the capacitive load of a finger is measured on each column or row electrode by a current meter, or the change in frequency of an RC oscillator.
A finger may be detected anywhere along the whole length of a row.
If that finger is also detected by a column, then it can be assumed that the finger position is at the intersection of this row/column pair.
This allows for the speedy and accurate detection of a single finger, but it causes some ambiguity if more than one finger is to be detected.
Two fingers may have four possible detection positions, only two of which are true. However, by selectively de-sensitizing any touch-points in contention, conflicting results are easily eliminated. This enables "Self Capacitance" to be used for multi-touch operation.
Alternatively, ambiguity can be avoided by applying a "de-sensitizing" signal to all but one of the columns .
This leaves just a short section of any row sensitive to touch. By selecting a sequence of these sections along the row, it is possible to determine the accurate position of multiple fingers along that row. This process can then be repeated for all the other rows until the whole screen has been scanned.
Self-capacitive touch screen layers are used on mobile phones such as the Sony Xperia Sola, the Samsung Galaxy S4
The Samsung Galaxy S4 is an Android smartphone produced by Samsung Electronics as the fourth smartphone of the Samsung Galaxy S series and was first shown publicly on March 14, 2013, at Samsung Mobile Unpacked in New York City. It is the succes ...
, Galaxy Note 3
The Samsung Galaxy Note 3 is an Android phablet smartphone produced by Samsung Electronics as part of the Samsung Galaxy Note series. The Galaxy Note 3 was unveiled on September 4, 2013, with its worldwide release beginning later in the month. S ...
, Galaxy S5
The Samsung Galaxy S5 is an Android-based smartphone unveiled, produced, released and marketed by Samsung Electronics as part of the Samsung Galaxy S series. Unveiled on 24 February 2014 at Mobile World Congress in Barcelona, Spain, it was rele ...
, and Galaxy Alpha
The Samsung Galaxy Alpha (SM-G850x) is an Android smartphone produced by Samsung Electronics. Unveiled on 13 August 2014, the device was released in September 2014. A high-end device, the Galaxy Alpha is Samsung's first Android-powered smartphon ...
.
Self capacitance is far more sensitive than mutual capacitance and is mainly used for single touch, simple gesturing and proximity sensing where the finger does not even have to touch the glass surface.
Mutual capacitance is mainly used for multitouch applications.
Many touchscreen manufacturers use both self and mutual capacitance technologies in the same product, thereby combining their individual benefits.
Use of stylus on capacitive screens
Capacitive touchscreens do not necessarily need to be operated by a finger, but until recently the special styli required could be quite expensive to purchase. The cost of this technology has fallen greatly in recent years and capacitive styli are now widely available for a nominal charge, and often given away free with mobile accessories. These consist of an electrically conductive shaft with a soft conductive rubber tip, thereby resistively connecting the fingers to the tip of the stylus.
Infrared grid
An infrared
Infrared (IR), sometimes called infrared light, is electromagnetic radiation (EMR) with wavelengths longer than those of visible light. It is therefore invisible to the human eye. IR is generally understood to encompass wavelengths from around ...
touchscreen uses an array of X-Y infrared LED
A light-emitting diode (LED) is a semiconductor Electronics, device that Light#Light sources, emits light when Electric current, current flows through it. Electrons in the semiconductor recombine with electron holes, releasing energy i ...
and photodetector
Photodetectors, also called photosensors, are sensors of light or other electromagnetic radiation. There is a wide variety of photodetectors which may be classified by mechanism of detection, such as Photoelectric effect, photoelectric or photoc ...
pairs around the edges of the screen to detect a disruption in the pattern of LED beams. These LED beams cross each other in vertical and horizontal patterns. This helps the sensors pick up the exact location of the touch. A major benefit of such a system is that it can detect essentially any opaque object including a finger, gloved finger, stylus or pen. It is generally used in outdoor applications and POS systems that cannot rely on a conductor (such as a bare finger) to activate the touchscreen. Unlike capacitive touchscreens, infrared touchscreens do not require any patterning on the glass which increases durability and optical clarity of the overall system. Infrared touchscreens are sensitive to dirt and dust that can interfere with the infrared beams, and suffer from parallax in curved surfaces and accidental press when the user hovers a finger over the screen while searching for the item to be selected.
Infrared acrylic projection
A translucent acrylic sheet is used as a rear-projection screen to display information. The edges of the acrylic sheet are illuminated by infrared LEDs, and infrared cameras are focused on the back of the sheet. Objects placed on the sheet are detectable by the cameras. When the sheet is touched by the user, frustrated total internal reflection
Total internal reflection (TIR) is the optical phenomenon in which waves arriving at the interface (boundary) from one medium to another (e.g., from water to air) are not refracted into the second ("external") medium, but completely reflected b ...
results in leakage of infrared light which peaks at the points of maximum pressure, indicating the user's touch location. Microsoft's PixelSense tablets use this technology.
Optical imaging
Optical touchscreens are a relatively modern development in touchscreen technology, in which two or more image sensors
An image sensor or imager is a sensor that detects and conveys information used to make an image. It does so by converting the variable attenuation of light waves (as they pass through or reflect off objects) into signals, small bursts of curr ...
(such as CMOS sensor
An active-pixel sensor (APS) is an image sensor where each pixel sensor unit cell has a photodetector (typically a pinned photodiode) and one or more active transistors. In a metal–oxide–semiconductor (MOS) active-pixel sensor, MOS field-effec ...
s) are placed around the edges (mostly the corners) of the screen. Infrared backlights are placed in the sensor's field of view on the opposite side of the screen. A touch blocks some lights from the sensors, and the location and size of the touching object can be calculated (see visual hull
A visual hull is a geometric entity created by shape-from-silhouette 3D reconstruction technique introduced by A. Laurentini. This technique assumes the foreground object in an image can be separated from the background. Under this assumption, ...
). This technology is growing in popularity due to its scalability, versatility, and affordability for larger touchscreens.
Dispersive signal technology
Introduced in 2002 by 3M, this system detects a touch by using sensors to measure the piezoelectricity
Piezoelectricity (, ) is the electric charge that accumulates in certain solid materials—such as crystals, certain ceramics, and biological matter such as bone, DNA, and various proteins—in response to applied mechanical stress. The word ''p ...
in the glass. Complex algorithms interpret this information and provide the actual location of the touch. The technology is unaffected by dust and other outside elements, including scratches. Since there is no need for additional elements on screen, it also claims to provide excellent optical clarity. Any object can be used to generate touch events, including gloved fingers. A downside is that after the initial touch, the system cannot detect a motionless finger. However, for the same reason, resting objects do not disrupt touch recognition.
Acoustic pulse recognition
The key to this technology is that a touch at any one position on the surface generates a sound wave in the substrate which then produces a unique combined signal as measured by three or more tiny transducers attached to the edges of the touchscreen. The digitized signal is compared to a list corresponding to every position on the surface, determining the touch location. A moving touch is tracked by rapid repetition of this process. Extraneous and ambient sounds are ignored since they do not match any stored sound profile. The technology differs from other sound-based technologies by using a simple look-up method rather than expensive signal-processing hardware. As with the dispersive signal technology system, a motionless finger cannot be detected after the initial touch. However, for the same reason, the touch recognition is not disrupted by any resting objects. The technology was created by SoundTouch Ltd in the early 2000s, as described by the patent family EP1852772, and introduced to the market by Tyco International
Tyco International plc was a security systems company incorporated in the Republic of Ireland, with operational headquarters in Princeton, New Jersey, United States (Tyco International (US) Inc.). Tyco International was composed of two major bu ...
's Elo division in 2006 as Acoustic Pulse Recognition. The touchscreen used by Elo is made of ordinary glass, giving good durability and optical clarity. The technology usually retains accuracy with scratches and dust on the screen. The technology is also well suited to displays that are physically larger.
Construction
There are several principal ways to build a touchscreen. The key goals are to recognize one or more fingers touching a display, to interpret the command that this represents, and to communicate the command to the appropriate application.
In the resistive approach, which used to be the most popular technique, there are typically four layers:
# Top polyester-coated layer with a transparent metallic-conductive coating on the bottom.
# Adhesive spacer
# Glass layer coated with a transparent metallic-conductive coating on the top
# Adhesive layer on the backside of the glass for mounting.
When a user touches the surface, the system records the change in the electric current that flows through the display.
Dispersive-signal technology measures the piezoelectric effect
Piezoelectricity (, ) is the electric charge that accumulates in certain solid materials—such as crystals, certain ceramics, and biological matter such as bone, DNA, and various proteins—in response to applied Stress (mechanics), mechanical s ...
—the voltage generated when mechanical force is applied to a material—that occurs chemically when a strengthened glass substrate is touched.
There are two infrared-based approaches. In one, an array of sensors detects a finger touching or almost touching the display, thereby interrupting infrared light beams projected over the screen. In the other, bottom-mounted infrared cameras
Infrared (IR), sometimes called infrared light, is electromagnetic radiation (EMR) with wavelengths longer than those of visible light. It is therefore invisible to the human eye. IR is generally understood to encompass wavelengths from around ...
record heat from screen touches.
In each case, the system determines the intended command based on the controls showing on the screen at the time and the location of the touch.
Development
The development of multi-touch screens facilitated the tracking of more than one finger on the screen; thus, operations that require more than one finger are possible. These devices also allow multiple users to interact with the touchscreen simultaneously.
With the growing use of touchscreens, the cost of touchscreen technology is routinely absorbed into the products that incorporate it and is nearly eliminated. Touchscreen technology has demonstrated reliability and is found in airplanes, automobiles, gaming consoles, machine control systems, appliances, and handheld display devices including cellphones; the touchscreen market for mobile devices was projected to produce US$5 billion by 2009.
The ability to accurately point on the screen itself is also advancing with the emerging graphics tablet-screen hybrids. Polyvinylidene fluoride
Polyvinylidene fluoride or polyvinylidene difluoride (PVDF) is a highly non-reactive thermoplastic fluoropolymer produced by the polymerization of vinylidene difluoride.
PVDF is a specialty plastic used in applications requiring the highest pur ...
(PVDF) plays a major role in this innovation due its high piezoelectric properties, which allow the tablet to sense pressure, making such things as digital painting behave more like paper and pencil.
TapSense, announced in October 2011, allows touchscreens to distinguish what part of the hand was used for input, such as the fingertip, knuckle and fingernail. This could be used in a variety of ways, for example, to copy and paste, to capitalize letters, to activate different drawing modes, etc.
A real practical integration between television-images and the functions of a normal modern PC could be an innovation in the near future: for example "all-live-information" on the internet about a film or the actors on video, a list of other music during a normal video clip
Video clips refer to mostly short videos, most of the time called memes, which are short videos of silly jokes and funny clips, most of the time coming from movies or any entertainment videos such as YouTube. The term is also used more loosely to ...
of a song or news about a person.
Ergonomics and usage
Touchscreen enable
For touchscreens to be effective input devices, users must be able to accurately select targets and avoid accidental selection of adjacent targets. The design of touchscreen interfaces should reflect technical capabilities of the system, ergonomics
Human factors and ergonomics (commonly referred to as human factors) is the application of psychological and physiological principles to the engineering and design of products, processes, and systems. Four primary goals of human factors learnin ...
, cognitive psychology
Cognitive psychology is the scientific study of mental processes such as attention, language use, memory, perception, problem solving, creativity, and reasoning.
Cognitive psychology originated in the 1960s in a break from behaviorism, which ...
and human physiology
The human body is the structure of a human being. It is composed of many different types of cells that together create tissues and subsequently organ systems. They ensure homeostasis and the viability of the human body.
It comprises a head ...
.
Guidelines for touchscreen designs were first developed in the 2000s, based on early research and actual use of older systems, typically using infrared grids—which were highly dependent on the size of the user's fingers. These guidelines are less relevant for the bulk of modern touch devices which use capacitive or resistive touch technology.
From the mid-2000s, makers of operating systems
An operating system (OS) is system software that manages computer hardware, software resources, and provides common services for computer programs.
Time-sharing operating systems schedule tasks for efficient use of the system and may also inc ...
for smartphones
A smartphone is a portable computer device that combines mobile telephone and computing functions into one unit. They are distinguished from feature phones by their stronger hardware capabilities and extensive mobile operating systems, which ...
have promulgated standards, but these vary between manufacturers, and allow for significant variation in size based on technology changes, so are unsuitable from a human factors
Human factors and ergonomics (commonly referred to as human factors) is the application of psychological and physiological principles to the engineering and design of products, processes, and systems. Four primary goals of human factors learnin ...
perspective.
Much more important is the accuracy humans have in selecting targets with their finger or a pen stylus. The accuracy of user selection varies by position on the screen: users are most accurate at the center, less so at the left and right edges, and least accurate at the top edge and especially the bottom edge. The R95 accuracy (required radius for 95% target accuracy) varies from in the center to in the lower corners. Users are subconsciously aware of this, and take more time to select targets which are smaller or at the edges or corners of the touchscreen.
This user inaccuracy is a result of parallax
Parallax is a displacement or difference in the apparent position of an object viewed along two different lines of sight and is measured by the angle or semi-angle of inclination between those two lines. Due to foreshortening, nearby objects ...
, visual acuity and the speed of the feedback loop between the eyes and fingers. The precision of the human finger alone is much, much higher than this, so when assistive technologies are provided—such as on-screen magnifiers—users can move their finger (once in contact with the screen) with precision as small as 0.1 mm (0.004 in).
Hand position, digit used and switching
Users of handheld and portable touchscreen devices hold them in a variety of ways, and routinely change their method of holding and selection to suit the position and type of input. There are four basic types of handheld interaction:
* Holding at least in part with both hands, tapping with a single thumb
* Holding with two hands and tapping with both thumbs
* Holding with one hand, tapping with the finger (or rarely, thumb) of another hand
* Holding the device in one hand, and tapping with the thumb from that same hand
Use rates vary widely. While two-thumb tapping is encountered rarely (1–3%) for many general interactions, it is used for 41% of typing interaction.
In addition, devices are often placed on surfaces (desks or tables) and tablets especially are used in stands. The user may point, select or gesture in these cases with their finger or thumb, and vary use of these methods.
Combined with haptics
Touchscreens are often used with haptic response systems. A common example of this technology is the vibratory feedback provided when a button on the touchscreen is tapped. Haptics are used to improve the user's experience with touchscreens by providing simulated tactile feedback, and can be designed to react immediately, partly countering on-screen response latency. Research from the University of Glasgow
, image = UofG Coat of Arms.png
, image_size = 150px
, caption = Coat of arms
Flag
, latin_name = Universitas Glasguensis
, motto = la, Via, Veritas, Vita
, ...
(Brewster, Chohan, and Brown, 2007; and more recently Hogan) demonstrates that touchscreen users reduce input errors (by 20%), increase input speed (by 20%), and lower their cognitive load (by 40%) when touchscreens are combined with haptics or tactile feedback. On top of this, a study conducted in 2013 by Boston College explored the effects that touchscreens haptic stimulation had on triggering psychological ownership of a product. Their research concluded that a touchscreens ability to incorporate high amounts of haptic involvement resulted in customers feeling more endowment to the products they were designing or buying. The study also reported that consumers using a touchscreen were willing to accept a higher price point for the items they were purchasing.
Customer service
Touchscreen technology has become integrated into many aspects of customer service industry in the 21st century. The restaurant industry is a good example of touchscreen implementation into this domain. Chain restaurants such as Taco Bell, Panera Bread, and McDonald's offer touchscreens as an option when customers are ordering items off the menu. While the addition of touchscreens is a development for this industry, customers may choose to bypass the touchscreen and order from a traditional cashier. To take this a step further, a restaurant in Bangalore has attempted to completely automate the ordering process. Customers sit down to a table embedded with touchscreens and order off an extensive menu. Once the order is placed it is sent electronically to the kitchen. These types of touchscreens fit under the Point of Sale (POS) systems mentioned in the lead section.
"Gorilla arm"
Extended use of gestural interfaces without the ability of the user to rest their arm is referred to as "gorilla arm". It can result in fatigue, and even repetitive stress injury when routinely used in a work setting. Certain early pen-based interfaces required the operator to work in this position for much of the workday. Allowing the user to rest their hand or arm on the input device or a frame around it is a solution for this in many contexts. This phenomenon is often cited as an example of movements to be minimized by proper ergonomic design.
Unsupported touchscreens are still fairly common in applications such as ATMs and data kiosks, but are not an issue as the typical user only engages for brief and widely spaced periods.
Fingerprints
Touchscreens can suffer from the problem of fingerprints on the display. This can be mitigated by the use of materials with optical coating
An optical coating is one or more thin layers of material deposited on an optical component such as a lens, prism or mirror, which alters the way in which the optic reflects and transmits light. These coatings have become a key technology in th ...
s designed to reduce the visible effects of fingerprint oils. Most modern smartphones have oleophobic Lipophobicity, also sometimes called lipophobia (from the Greek λιποφοβία from λίπος ''lipos'' "fat" and φόβος ''phobos'' "fear"), is a chemical property of chemical compounds which means "fat rejection", literally "fear of fat". ...
coatings, which lessen the amount of oil residue. Another option is to install a matte-finish anti-glare screen protector
A screen protector is an additional sheet of material—commonly polyurethane or laminated glass—that can be attached to the screen of an electronic device and protect it against physical damage.
History
The first screen protector was design ...
, which creates a slightly roughened surface that does not easily retain smudges.
Glove touch
Touchscreens do not work most of the time when the user wears gloves. The thickness of the glove and the material they are made of play a significant role on that and the ability of a touchscreen to pick up a touch.
See also
* Dual-touchscreen
A dual-touchscreen is a computer or phone display setup which uses two screens, either or both of which could be touch-capable, to display both elements of the computer's graphical user interface and virtualized implementations of common input dev ...
* Pen computing
Pen computing refers to any computer user-interface using a pen or stylus and tablet, over input devices such as a keyboard or a mouse.
Pen computing is also used to refer to the usage of mobile devices such as tablet computers, PDAs and GPS recei ...
* Energy harvesting
Energy harvesting (EH, also known as power harvesting or energy scavenging or ambient power) is the process by which energy is derived from external sources (e.g., solar power, thermal energy, wind energy, salinity gradients, and kinetic energ ...
* Flexible keyboard
The technology of computer keyboards includes many elements. Among the more important of these is the switch technology that they use. Computer alphanumeric keyboards typically have 80 to 110 durable switches, generally one for each key. The ch ...
* Gestural interface
Gesture recognition is a topic in computer science and language technology with the goal of interpreting human gestures via mathematical algorithms. It is a subdiscipline of computer vision. Gestures can originate from any bodily motion or sta ...
* Graphics tablet
A graphics tablet (also known as a digitizer, digital graphic tablet, pen tablet, drawing tablet, external drawing pad or digital art board) is a computer input device that enables a user to hand-draw images, animations and graphics, with a spec ...
* Light pen
A light pen is a computer input device in the form of a light-sensitive wand used in conjunction with a computer's cathode-ray tube (CRT) display.
It allows the user to point to displayed objects or draw on the screen in a similar way to a tou ...
* List of touch-solution manufacturers
A list of the manufacturers of components that are specific to touch solutions.
Touchscreens
Capacitive
*Elo Touch Solutions, Inc.
* 3M
*Alps Electric Corporation
*Atmel
*Cirque
*Cypress
* SCHURTER Input Systems
*Synaptics
* TouchNetix
Proj ...
* Lock screen
A lock screen is a computer user interface element used by various operating systems. They regulate immediate access to a device by requiring the user to perform a certain action in order to receive access, such as entering a password, using a cert ...
* Tablet computer
A tablet computer, commonly shortened to tablet, is a mobile device, typically with a mobile operating system and touchscreen display processing circuitry, and a rechargeable battery in a single, thin and flat package. Tablets, being comput ...
* Touch switch A touch switch is a type of switch
In electrical engineering, a switch is an electrical component that can disconnect or connect the conducting path in an electrical circuit, interrupting the electric current or diverting it from one conductor ...
* Touchscreen remote control
In electronics, a remote control (also known as a remote or clicker) is an electronic device used to operate another device from a distance, usually wirelessly. In consumer electronics, a remote control can be used to operate devices such as ...
* Multi-touch
In computing, multi-touch is technology that enables a surface (a touchpad or touchscreen) to recognize the presence of more than one somatosensory system, point of contact with the surface at the same time. The origins of multitouch began at CER ...
* Omnitouch
* Pointing device gesture
In computing, a pointing device gesture or mouse gesture (or simply gesture) is a way of combining pointing device or finger movements and clicks that the software recognizes as a specific computer event and responds to accordingly. They can be ...
* Sensacell
Sensacell is an interactive interface technology developed by the Sensacell Corporation. A Sensacell surface functions is an interactive touchscreen display, but on a large-scale framework. Individual tile-like modules—each containing LED (Light ...
* SixthSense
SixthSense is a gesture-based wearable computer system developed at MIT Media Lab by Steve Mann in 1994 and 1997 (headworn gestural interface), and 1998 (neckworn version), and further developed by Pranav Mistry (also at MIT Media Lab), in 200 ...
* Nintendo DS
The is a handheld game console produced by Nintendo, released globally across 2004 and 2005. The DS, an initialism for "Developers' System" or "Dual Screen", introduced distinctive new features to handheld games: two LCD screens working in tan ...
References
Sources
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External links
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American inventions
European inventions
Display devices