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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. Touchpads are a common feature of
laptop computer A laptop or laptop computer is a small, portable personal computer File:Crystal Project computer.png, upright=0.9, An artist's depiction of a 2000s-era desktop-style personal computer, which includes a metal case with the computing compone ...

laptop computer
s as opposed to using a mouse on a desktop, and are also used as a substitute for a
mouse A mouse, plural mice, is a small mammal Mammals (from Latin language, Latin , 'breast') are a group of vertebrate animals constituting the class (biology), class Mammalia (), and characterized by the presence of mammary glands which ...

mouse
where desk space is scarce. Because they vary in size, they can also be found on
personal digital assistant#REDIRECT Personal digital assistant The Palm TX 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 widesprea ...
s (PDAs) and some
portable media player A portable media player (PMP) or digital audio player (DAP) is a portable consumer electronics Consumer electronics or home electronics are electronic ( analog or digital) equipment intended for everyday use, typically in private homes. C ...
s. Wireless touchpads are also available as detached accessories.


Operation and function

Touchpads operate in one of several ways, including
capacitive sensing In electrical engineering, capacitive sensing (sometimes capacitance sensing) is a technology, based on capacitive coupling, that can detect and measure anything that is conductive or has a dielectric A dielectric (or dielectric material) is a ...
or
resistive touchscreen In electrical engineering Electrical engineering is an engineering discipline concerned with the study, design, and application of equipment, devices, and systems which use electricity, electronics The field of electronics is a branch of ph ...
. The most common technology used in the 2010s senses the change of
capacitance Capacitance is the ratio of the amount of stored on a to a difference in . There are two closely related notions of capacitance: ''self capacitance'' and ''mutual capacitance''. Any object that can be electrically charged exhibits ''self capa ...
where a finger touches the pad. Capacitance-based touchpads will not sense the tip of a pencil or other similar ungrounded or non-conducting implements. Fingers insulated by a glove may also be problematic, and capacitive touchpads are rarely used as pointing devices for medical hardware. While touchpads, like touchscreens, are able to sense absolute position, resolution is limited by their size. For common use as a pointer device, the dragging motion of a finger is translated into a finer, relative motion of the cursor on the output to the display on the operating system, analogous to the handling of a
mouse A mouse, plural mice, is a small mammal Mammals (from Latin language, Latin , 'breast') are a group of vertebrate animals constituting the class (biology), class Mammalia (), and characterized by the presence of mammary glands which ...
that is lifted and put back on a surface. Hardware buttons equivalent to a standard mouse's left and right buttons are sometimes positioned adjacent to the touchpad. Some touchpads and associated
device driver In computing Computing is any goal-oriented activity requiring, benefiting from, or creating computing machinery. It includes the study and experimentation of algorithmic processes and development of both computer hardware , hardware and softwa ...
software may interpret tapping the pad as a
mouse click In programming and software design Software design is the process by which an Agency (philosophy), agent creates a specification of a Artifact (software development), software artifact intended to accomplish goals, using a set of primitive comp ...
, and a tap followed by a continuous pointing motion (a "click-and-a-half") can indicate dragging. Tactile touchpads allow for clicking and dragging by incorporating button functionality into the surface of the touchpad itself. To select, one presses down on the touchpad instead of a physical button. To drag, instead of performing the "click-and-a-half" technique, the user presses down while on the object, drags without releasing pressure, and lets go when done. Touchpad drivers can also allow the use of multiple fingers to emulate the other mouse buttons (commonly two-finger tapping for the center button). Touchpads are called clickpads if it does not have physical buttons, but instead relies on "software buttons". Physically the whole clickpad formed a button, logically the driver interprets a click as a left or right button click depending on the placement of fingers. Some touchpads have "hotspots", locations on the touchpad used for functionality beyond a mouse. For example, on certain touchpads, moving the finger along an edge of the touch pad will act as a
scroll wheel A scroll wheel is a wheel used for scrolling. The term usually refers to such wheels found on computer mouse, computer mice (where they can also be called a mouse wheel). It is often made of hard plastic with a rubbery surface, based around an i ...
, controlling the
scrollbar A scrollbar is an interaction technique or widget in which continuous text, pictures, or any other content can be scrolled in a predetermined direction (up, down, left, or right) on a computer display A computer monitor is an output device th ...

scrollbar
and scrolling the
window A window is an opening in a wall A wall is a structure and a surface that defines an area; carries a load; provides , , or ; or, is decorative. There are many kinds of walls, including: * Walls in buildings that form a fundamental part of ...
that has the
focus FOCUS is a fourth-generation programming language (4GL) computer programming programming language, language and development environment that is used to build database queries. Produced by Information Builders Inc., it was originally developed for d ...
, vertically or horizontally. Many touchpads use two-finger dragging for
scrolling In computer display A computer monitor is an output device that displays information in pictorial or text form. A monitor usually comprises a electronic visual display, visual display, electronic circuit, some circuitry, a casing, and a power ...
. Also, some touchpad drivers support tap zones, regions where a tap will execute a function, for example, pausing a media player or launching an
application Application may refer to: Mathematics and computing * Application software, computer software designed to help the user to perform specific tasks ** Application layer, an abstraction layer that specifies protocols and interface methods used in a co ...
. All of these functions are implemented in the touchpad
device driver In computing Computing is any goal-oriented activity requiring, benefiting from, or creating computing machinery. It includes the study and experimentation of algorithmic processes and development of both computer hardware , hardware and softwa ...
software, and can be disabled.


History

By 1982,
Apollo Apollo, grc, Ἀπόλλωνος, ''Apóllōnos'', label=genitive , ; , grc-dor, Ἀπέλλων, ''Apéllōn'', ; grc, Ἀπείλων, ''Apeílōn'', label=Arcadocypriot Greek, ; grc-aeo, Ἄπλουν, ''Áploun'', la, Apollō, ...
desktop computers were equipped with a touchpad on the right side of the keyboard. Introduced a year later, in 1983, the first battery powered clamshell laptop, the
Gavilan SC The Gavilan SC was a laptop A laptop, laptop computer, or notebook computer is a small, portable personal computer File:Crystal Project computer.png, upright=0.9, An artist's depiction of a 2000s-era desktop-style personal computer, whic ...

Gavilan SC
included a touchpad, which was mounted above its keyboard, rather than below, which became the norm. Psion's MC 200/400/600/WORD Series, introduced in 1989, came with a new mouse-replacing input device similar to a touchpad, although more closely resembling a
graphics tablet A graphics tablet (also known as a digitizer, digital graphic tablet, pen tablet, or digital art board) is a computer input device In computing, an input device is a piece of equipment used to provide data and control signals to an information ...
, as the cursor was positioned by clicking on a specific point on the pad, instead of moving it in the direction of a stroke. Laptops with touchpads were then launched by
Olivetti Olivetti S.p.A. is an Italy, Italian manufacturer of computers, Tablet computer, tablets, smartphones, Printer (computing), printers and other such business products as calculators and Fax Machine, fax machines. Headquartered in Ivrea, in the Me ...

Olivetti
and Triumph-Adler in 1992.
Cirque A cirque (; from the Latin word ''circus'') is an amphitheatre An amphitheatre ( British English) or amphitheater ( American English; both ) is an open-air venue used for entertainment, performances, and sports. The term derives from the an ...
introduced the first widely available touchpad, branded as GlidePoint, in 1994.
Apple An apple is an edible fruit produced by an apple tree (''Malus domestica''). Apple fruit tree, trees are agriculture, cultivated worldwide and are the most widely grown species in the genus ''Malus''. The tree originated in Central Asia, wher ...
introduced touchpads with modern placing in the PowerBook 500 series in 1994, using Cirque's GlidePoint technology, which Apple refers to as a "trackpad"; it replaced the
trackball A trackball is a consisting of a held by a socket containing sensors to detect a rotation of the ball about two axes—like an upside-down with an exposed protruding ball. Users roll the ball to position the on-screen , using their , s, or co ...

trackball
of previous
PowerBook The PowerBook (known as Macintosh PowerBook before 1997) is a family of Macintosh Macintosh 128k The Macintosh 128K, originally released as the Apple Macintosh, is the original Apple Inc., Apple Macintosh personal computer. Its beige case ...
models. Since 2008 Apple's revisions of the
MacBook The MacBook is a brand of Macintosh Macintosh 128k The Macintosh 128K, originally released as the Apple Macintosh, is the original Apple Inc., Apple Macintosh personal computer. Its beige case consisted of a CRT monitor and came with a ...

MacBook
and
MacBook Pro The MacBook Pro is a line of Macintosh Laptop, notebook computers introduced in January 2006 by Apple Inc. It is the higher-end model of the MacBook family, sitting above the consumer-focused MacBook Air, and is currently sold with 13-inch, 14 ...

MacBook Pro
incorporated a "Tactile Touchpad" design with button integrated into the tracking surface (the entire touchpad surface acts as a clickable button). Another early adopter of the GlidePoint pointing device was Sharp. Later,
Synaptics Synaptics is a publicly owned San Jose, California San Jose, officially San José (; ; ), is the cultural, financial, and political center of Silicon Valley, and the largest city in Northern California by both population and area. With an estim ...
introduced their touchpad into the marketplace, branded the TouchPad, and
Epson Seiko Epson Corporation, or simply known as Epson, is a Japanese electronics The field of electronics is a branch of physics and electrical engineering that deals with the emission, behaviour and effects of electrons The electron is a ...
was an early adopter of this product with their ActionNote. As touchpads began to be introduced in laptops in the 1990s, there was often confusion as to what the product should be called. No consistent term was used, and references varied, such as: glidepoint, touch sensitive input device, touchpad, trackpad, and pointing device. Users were often presented the option to purchase a
pointing stick ] A pointing stick (or trackpoint, also referred to generically as a nub) is a small analog stick used as a pointing device typically mounted centrally in a computer keyboard. Like other pointing devices such as computer mouse, mice, touchpads o ...
, touchpad, or
trackball A trackball is a consisting of a held by a socket containing sensors to detect a rotation of the ball about two axes—like an upside-down with an exposed protruding ball. Users roll the ball to position the on-screen , using their , s, or co ...

trackball
. Combinations of the devices were common, though touchpads and trackballs were rarely included together. Since the early 2000s, touchpads have become the dominant laptop pointing device as most consumer laptops produced during this period beyond include only touchpads, displacing the pointing stick.


Use in devices

Touchpads are primarily used in self-contained portable
laptop A laptop, laptop computer, or notebook computer is a small, portable personal computer A personal computer (PC) is a multi-purpose computer whose size, capabilities, and price make it feasible for individual use. Personal computers are ...

laptop
computers and do not require a flat surface near the machine. The touchpad is close to the keyboard, and relatively short finger movements are required to move the cursor across the display screen; while advantageous, this also makes it possible for a user's palm or wrist to move the mouse cursor accidentally while typing. Laptops today feature multitouch touchpads that can sense in some cases up to five fingers simultaneously, providing more options for input, such as the ability to bring up the
context menu A context menu (also called contextual, shortcut, and pop up or pop-up menu) is a Menu (computing), menu in a graphical user interface (GUI) that appears upon user interaction, such as a right-click Mouse (computing)#Operation, mouse operatio ...

context menu
by tapping two fingers, dragging two fingers for scrolling, or gestures for zoom in/out or rotate. The touchpads with physical buttons now are only hi-end business\professional laptops option. One-dimensional touchpads are the primary control interface for menu navigation on
iPod Classic The iPod Classic (stylized and marketed as iPod classic and formerly iPod Video or just iPod) is a discontinued portable media player A portable media player (PMP) or digital audio player (DAP) is a portable consumer electronics Consu ...

iPod Classic
portable music players and additional input method on some
Wacom () is a Japanese company headquartered in Kazo, Saitama, Japan, that specializes in graphics tablets and related products. Headquarters locations The American headquarters are located in the Pearl District, Portland, Oregon, Pearl District of ...
digitizer tablets, where they are referred to as "click wheels", since they only sense motion along one axis, which is wrapped around like a wheel.
Creative Labs Creative Technology Ltd. is a Singaporean multinational technology company headquartered in Jurong East, Singapore, with overseas offices in Shanghai, Tokyo Tokyo ( , ; Japanese language, Japanese: 東京, ''Tōkyō'' ), officially ...
also uses a touchpad for their
Zen Zen ( zh, t=禪, p=Chán; ja, text= 禅, translit=zen; ko, text=선, translit=Seon; vi, text=Thiền) is a school of Mahayana Buddhism that originated in China China, officially the People's Republic of China (PRC), is a country i ...
line of
MP3 player#REDIRECT MP3 MP3 (formally MPEG-1 Audio Layer III or MPEG-2 Audio Layer III) is a coding format for digital audio Digital audio is a representation of sound recorded in, or converted into, Digital signal (signal processing), digital form. ...
s, beginning with the Zen Touch. The second-generation
Microsoft Microsoft Corporation is an American multinational corporation, multinational technology company, technology corporation which produces Software, computer software, consumer electronics, personal computers, and related services. Its best-know ...

Microsoft
Zune Zune is a discontinued line of digital media Digital media means any communication media that operate with the use of any of various encoded machine-readable data Machine-readable data, or computer-readable data, is data Data are units o ...

Zune
product line (the Zune 80/120 and Zune 4/8) uses touch for the
Zune Pad#REDIRECT Zune Pad The Zune Pad, which is a squircle, is the primary control wikt:mechanism, mechanism for Zune 4, 8, 16, Zune 80, 120, 80 and 120. The pad lets users of this device scroll through their song list with the use of their finger, then p ...
. Touchpads also exist for desktop computers as an external peripheral, albeit rarely seen. But touchpad layer can be integrated with
graphics tablet A graphics tablet (also known as a digitizer, digital graphic tablet, pen tablet, or digital art board) is a computer input device In computing, an input device is a piece of equipment used to provide data and control signals to an information ...
as additional input option. External computer keyboards can be equipped with integrated touchpads (particularly keyboards oriented for
HTPC A home theater PC (HTPC) or media center computer is a convergent Convergent is an adjective for things that wikt:converge, converge. It is commonly used in mathematics and may refer to: *Convergent boundary, a type of plate tectonic boundary ...
use), and some keyboards can have only touch input surface instead of hardware buttons (as typical solution for clean rooms). Optical trackpads primary can be used as part of ultraportable electronics; some handheld laptops and early smartphones can be equipped with optical trackpads.


Theory of operation

There are two principal means by which touchpads work. In the ''matrix approach'', a series of
conductors Conductor or conduction may refer to: Music * Conductor (music), a person who leads a musical ensemble like, for example, an orchestra. * Conductor (album), ''Conductor'' (album), an album by indie rock band The Comas * Conduction, a type of ...
are arranged in an array of parallel lines in two layers, separated by an
insulator Insulator may refer to: * Insulator (electricity), a substance that resists electricity ** Pin insulator, a device that isolates a wire from a physical support such as a pin on a utility pole ** Strain insulator, a device that is designed to work i ...
and crossing each other at
right angle In geometry Geometry (from the grc, γεωμετρία; ' "earth", ' "measurement") is, with , one of the oldest branches of . It is concerned with properties of space that are related with distance, shape, size, and relative position ...

right angle
s to form a grid. A high frequency signal is applied sequentially between pairs in this two-dimensional grid array. The current that passes between the nodes is proportional to the
capacitance Capacitance is the ratio of the amount of stored on a to a difference in . There are two closely related notions of capacitance: ''self capacitance'' and ''mutual capacitance''. Any object that can be electrically charged exhibits ''self capa ...
. When a
virtual groundIn electronics Electronics comprises the physics, engineering, technology and applications that deal with the emission, flow and control of electrons in vacuum and matter. It uses active devices to control electron flow by amplifier, amplificatio ...

virtual ground
, such as a finger, is placed over one of the intersections between the conductive layer some of the electrical field is shunted to this ground point, resulting in a change in the apparent capacitance at that location. This method received awarded to George Gerpheide in April 1994. The ''capacitive shunt method'', described in an application note by manufacturer
Analog Devices Analog Devices, Inc. (ADI), also known simply as Analog, is an American multinational semiconductor company specializing in data conversion Data conversion is the conversion of computer data from one format to another. Throughout a computer ...
, senses the change in
capacitance Capacitance is the ratio of the amount of stored on a to a difference in . There are two closely related notions of capacitance: ''self capacitance'' and ''mutual capacitance''. Any object that can be electrically charged exhibits ''self capa ...
between a transmitter and receiver that are on opposite sides of the sensor. The transmitter creates an electric field which oscillates at 200–300 kHz. If a ground point, such as the finger, is placed between the transmitter and receiver, some of the field lines are shunted away, decreasing the apparent capacitance. Trackpads such as those found in some Blackberry smartphones work optically, like an optical
computer mouse A computer mouse (plural mice, sometimes mouses) is a hand-held pointing device A pointing device is a human interface device A human interface device or HID is a type of computer device usually used by humans that takes input fro ...

computer mouse
.


Manufacturing

Major manufacturers include: *
Alps Electric Corporation is a Japanese multinational corporation, headquartered in Tokyo, Japan, producing electronic devices, including switches, potentiometers, sensors, encoders and touchpads. The company was established in 1948 as Kataoka Electric Co., Ltd. and chang ...
* Elan Microelectronics *
Cirque Corporation Cirque Corporation is an American company which developed and commercialized the first successful capacitive touchpad A touchpad or trackpad is a pointing device featuring a tactile sensor, a specialized surface that can translate the motion a ...
*
Synaptics Synaptics is a publicly owned San Jose, California San Jose, officially San José (; ; ), is the cultural, financial, and political center of Silicon Valley, and the largest city in Northern California by both population and area. With an estim ...


See also

*
Capacitive sensing In electrical engineering, capacitive sensing (sometimes capacitance sensing) is a technology, based on capacitive coupling, that can detect and measure anything that is conductive or has a dielectric A dielectric (or dielectric material) is a ...
*
Graphics pad A graphics tablet (also known as a digitizer, drawing tablet, drawing pad, digital drawing tablet, pen tablet, or digital art board) is a computer input device In computing Computing is any goal-oriented activity requiring, benefiting from, ...
*
Kaoss pad The Kaoss Pad is an Effects unit, audio effects unit launched by Korg in 1999. Features vary across models, but Kaoss Pads generally allow users to Sampling (music), sample and Loop (music), loop audio and apply effects such as Pitch shift, pitch-b ...
*
List of touch-solution manufacturers A list of the manufacturers of components that are specific to touch solutions. Touchscreens Capacitive *Miracletouch Technology Inc *DMC Co. Ltd *TSItouch Inc. * 3M *Alps Electric Corporation is a Japanese multinational corporation, headqua ...
*
Magic Trackpad 2 The Magic Trackpad 2 is a multi-touch 250px, Finger touching a multi-touch screen 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 o ...

Magic Trackpad 2
*
Multi-touch In computing Computing is any goal-oriented activity requiring, benefiting from, or creating computing machinery. It includes the study and experimentation of algorithm of an algorithm (Euclid's algorithm) for calculating the greatest commo ...
*
Pointing stick ] A pointing stick (or trackpoint, also referred to generically as a nub) is a small analog stick used as a pointing device typically mounted centrally in a computer keyboard. Like other pointing devices such as computer mouse, mice, touchpads o ...


References


External links


Annotated Bibliography of References to Gestures, Touchscreens, and Pen Computing
* {{Authority control History of human–computer interaction Pointing devices