Touchpad

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Closeup of a touchpad on an Acer CB5-311 laptop Acer CB5-311 series touchpad.jpg
Closeup of a touchpad on an Acer CB5-311 laptop
Closeup of a touchpad on a MacBook 2015 laptop Macbook touchpad.jpg
Closeup of a touchpad on a MacBook 2015 laptop

A touchpad or trackpad is a type of pointing device. Its largest component is a tactile sensor: an electronic device with a flat surface, that detects the motion and position of a user's fingers, and translates them to a position on a screen, to control a pointer in a graphical user interface. Touchpads are common on laptop computers, contrasted with desktop computers, where mice are more prevalent. Trackpads are sometimes used on desktops, where desk space is scarce. Because trackpads can be made small, they can be found on personal digital assistants (PDAs) and some portable media players. Wireless touchpads are also available, as detached accessories.

Contents

Operation and function

Touchpads operate in several ways, including capacitive sensing or resistive touchscreen. The most common technology used in the 2010s senses the change of capacitance 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. [1]

Like touchscreens, touchpads sense absolute position but their 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 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 software may interpret tapping the pad as a mouse click, and a tap followed by a continuous pointing motion (a "click-and-a-half") can indicate dragging. [2] Tactile touchpads allow for clicking and dragging by incorporating button functionality into the surface of the touchpad itself. [3] [4] 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 right click).

Touchpads are called clickpads if they rely on software buttons rather than physical 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. [5]

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, controlling the scrollbar and scrolling the window that has the focus, vertically or horizontally. Many touchpads use two-finger dragging for scrolling. 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. All of these functions are implemented in the touchpad device driver software, and can be disabled.

History

By 1982, Apollo desktop computers were equipped with a touchpad on the right side of the keyboard. [6] Introduced a year later, in 1983, the first battery-powered clamshell laptop, the Gavilan SC included a touchpad, which was mounted above its keyboard, rather than below, which became the norm. [7]

Psion's MC 200/400/600/WORD Series, [8] introduced in 1989, came with a new mouse-replacing input device similar to a touchpad, [9] although more closely resembling a graphics tablet, as the cursor was positioned by clicking on a specific point on the pad, instead of moving it in the direction of a stroke. [10]

Laptops with touchpads were then launched by Olivetti and Triumph-Adler in 1992. [11] Cirque introduced the first widely available touchpad, branded as GlidePoint, in 1994. [12] [13] Apple introduced touchpads with modern placing in the PowerBook 500 series in 1994, using Cirque's GlidePoint technology, [14] [15] which Apple refers to as a "trackpad"; it replaced the trackball of previous PowerBook models. Since 2008, Apple's revisions of the MacBook and MacBook Pro incorporated a "Tactile Touchpad" design with a button integrated into the tracking surface [3] [4] [16] (the lower part of the touchpad surface acts as a clickable button). [17]

Another early adopter of the GlidePoint pointing device was Sharp. [12] Later, Synaptics introduced their touchpad into the marketplace, branded the TouchPad, and Epson was an early adopter of this product with their ActionNote. [12] 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. [18] [19] [20]

Users were often presented with the option to purchase a pointing stick, touchpad, or trackball. Combinations of the devices were common, though touchpads and trackballs were rarely included together. [21] Since the early 2000s, touchpads have become the dominant laptop pointing device as most consumer laptops produced during this period and beyond includes only touchpads, displacing the pointing stick.

Use in devices

Optical trackpad of the BlackBerry Curve 8520 in the red circle Curve8520TrackPad.jpg
Optical trackpad of the BlackBerry Curve 8520 in the red circle
A Microsoft Surface tablet. The touchpad is the rectangle near the bottom of the gray keyboard. Surface RT.jpg
A Microsoft Surface tablet. The touchpad is the rectangle near the bottom of the gray keyboard.

Touchpads are primarily used in self-contained portable 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 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 portable music players and additional input method on some Wacom 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 also uses a touchpad for their Zen line of MP3 players, beginning with the Zen Touch. The second-generation Microsoft Zune product line (the Zune 80/120 and Zune 4/8) uses touch for the Zune Pad.

Touchpads also exist for desktop computers as an external peripheral, albeit rarely seen. But touchpad layer can be integrated with graphics tablet as additional input option.

External computer keyboards can be equipped with integrated touchpads [22] (particularly keyboards oriented for HTPC use), and some keyboards can have only touch input surface instead of hardware buttons (a typical solution for clean rooms). [23]

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.[ citation needed ] In the matrix approach, a series of conductors are arranged in an array of parallel lines in two layers, separated by an insulator and crossing each other at right angles 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. When a 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 U.S. patent 5,305,017 awarded to George Gerpheide in April 1994.

The capacitive shunt method, described in an application note by manufacturer Analog Devices, [24] senses the change in capacitance 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.

Manufacturing

Major manufacturers include:[ citation needed ]

See also

Related Research Articles

<span class="mw-page-title-main">Computer mouse</span> Pointing device used to control a computer

A computer mouse is a hand-held pointing device that detects two-dimensional motion relative to a surface. This motion is typically translated into the motion of the pointer on a display, which allows a smooth control of the graphical user interface of a computer.

<span class="mw-page-title-main">Pointing device gesture</span>

In computing, a pointing device gesture or mouse 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 useful for people who have difficulties typing on a keyboard. For example, in a web browser, a user can navigate to the previously viewed page by pressing the right pointing device button, moving the pointing device briefly to the left, then releasing the button.

<span class="mw-page-title-main">Pointing device</span> Human interface device for computers

A pointing device is a human interface device that allows a user to input spatial data to a computer. CAD systems and graphical user interfaces (GUI) allow the user to control and provide data to the computer using physical gestures by moving a hand-held mouse or similar device across the surface of the physical desktop and activating switches on the mouse. Movements of the pointing device are echoed on the screen by movements of the pointer and other visual changes. Common gestures are point and click and drag and drop.

<span class="mw-page-title-main">Trackball</span> Pointing device

A trackball is a pointing device consisting of a ball held by a socket containing sensors to detect a rotation of the ball about two axes—like an upside-down ball mouse with an exposed protruding ball. Users roll the ball to position the on-screen pointer, using their thumb, fingers, or the palm of the hand, while using the fingertips to press the buttons.

<span class="mw-page-title-main">Graphics tablet</span> Computer input device

A graphics tablet is a computer input device that enables a user to hand-draw images, animations and graphics, with a special pen-like stylus, similar to the way a person draws images with a pencil and paper.

<span class="mw-page-title-main">Scrollbar</span> Graphical user interface element

A scrollbar is an interaction technique or widget in which continuous text, pictures, or any other content can be scrolled in a predetermined direction on a computer display, window, or viewport so that all of the content can be viewed, even if only a fraction of the content can be seen on a device's screen at one time. It offers a solution to the problem of navigation to a known or unknown location within a two-dimensional information space. It was also known as a handle in the very first GUIs. They are present in a wide range of electronic devices including computers, graphing calculators, mobile phones, and portable media players. The user interacts with the scrollbar elements using some method of direct action, the scrollbar translates that action into scrolling commands, and the user receives feedback through a visual updating of both the scrollbar elements and the scrolled content.

<span class="mw-page-title-main">Pointing stick</span> Isometric joystick typically mounted in a keyboard

A pointing stick is a small analog stick used as a pointing device typically mounted centrally in a computer keyboard. Like other pointing devices such as mice, touchpads or trackballs, operating system software translates manipulation of the device into movements of the pointer on the computer screen. Unlike other pointing devices, it reacts to sustained force or strain rather than to gross movement, so it is called an "isometric" pointing device. IBM introduced it commercially in 1992 on its laptops under the name "TrackPoint", and patented an improved version of it in 1997. It has been used for business laptops, such as Acer's TravelMate, Dell's Latitude, HP's EliteBook and Lenovo's ThinkPad.

Cirque Corporation is an American company which developed and commercialized the first successful capacitive touchpad, now widely used in notebook computers. Cirque develops and sells a variety of touch input products, both in original equipment manufacturer and end-user retail form. Cirque was founded in 1991 by George E. Gerpheide, PhD, and James L. O'Callaghan, to commercialize the GlidePoint technology invented in the 1980s by Gerpheide.

<span class="mw-page-title-main">Touchscreen</span> Input and output device

A touchscreen is a type of display that can detect touch input from a user. It consists of both an input device and an output device. The touch panel is typically layered on the top of the electronic visual display of a device. Touchscreens are commonly found in smartphones, tablets, laptops, and other electronic devices.

Synaptics Incorporated is a publicly owned San Jose, California-based developer of human interface (HMI) hardware and software, including touchpads for computer laptops; touch, display driver, and fingerprint biometrics technology for smartphones; and touch, video and far-field voice technology for smart home devices and automotives. Synaptics sells its products to original equipment manufacturers (OEMs) and display manufacturers.

<span class="mw-page-title-main">Scroll wheel</span> Component of a computer mouse used for scrolling

A scroll wheel is a wheel used for scrolling. The term usually refers to such wheels found on computer mice. It is often made of hard plastic with a rubbery surface, centred around an internal rotary encoder. It is usually located between the left and right mouse buttons and is positioned perpendicular to the mouse surface. Sometimes the wheel can be pressed left and right, which is actually just two additional macros buttons.

In human–computer interaction, a cursor is an indicator used to show the current position on a computer monitor or other display device that will respond to input.

<span class="mw-page-title-main">Multi-touch</span> Technology

In computing, multi-touch is technology that enables a surface to recognize the presence of more than one point of contact with the surface at the same time. The origins of multitouch began at CERN, MIT, University of Toronto, Carnegie Mellon University and Bell Labs in the 1970s. CERN started using multi-touch screens as early as 1976 for the controls of the Super Proton Synchrotron. Capacitive multi-touch displays were popularized by Apple's iPhone in 2007. Multi-touch may be used to implement additional functionality, such as pinch to zoom or to activate certain subroutines attached to predefined gestures using gesture recognition.

<span class="mw-page-title-main">Pen computing</span> Uses a stylus and tablet/touchscreen

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.

<span class="mw-page-title-main">Apple pointing devices</span> Computer pointing devices made by Apple

Apple Inc. has designed and manufactured several models of mice, trackpads, and other pointing devices, primarily for use with Macintosh computers. Over the years, Apple has maintained a distinct form and function with its mice that reflect their design languages of that time. Apple's current external pointing devices are the Magic Mouse 2 and Magic Trackpad 2.

In electrical engineering, capacitive sensing is a technology, based on capacitive coupling, that can detect and measure anything that is conductive or has a dielectric constant different from air. Many types of sensors use capacitive sensing, including sensors to detect and measure proximity, pressure, position and displacement, force, humidity, fluid level, and acceleration. Human interface devices based on capacitive sensing, such as touchpads, can replace the computer mouse. Digital audio players, mobile phones, and tablet computers will sometimes use capacitive sensing touchscreens as input devices. Capacitive sensors can also replace mechanical buttons.

<span class="mw-page-title-main">Input device</span> Device that provides data and signals to a computer

In computing, an input device is a piece of equipment used to provide data and control signals to an information processing system, such as a computer or information appliance. Examples of input devices include keyboards, computer mice, scanners, cameras, joysticks, and microphones.

<span class="mw-page-title-main">Stylus (computing)</span> Pen-shaped instrument used as a human-computer interface

In computing, a stylus is a small pen-shaped instrument whose tip position on a computer monitor can be detected. It is used to draw, or make selections by tapping. While devices with touchscreens such as newer computers, mobile devices, game consoles, and graphics tablets can usually be operated with a fingertip, a stylus provides more accurate and controllable input. The stylus has the same function as a mouse or touchpad as a pointing device; its use is commonly called pen computing.

<span class="mw-page-title-main">Microsoft Tablet PC</span> Microsofts former line of tablets

Microsoft Tablet PC is a term coined by Microsoft for tablet computers conforming to a set of specifications announced in 2001 by Microsoft, for a pen-enabled personal computer, conforming to hardware specifications devised by Microsoft and running a licensed copy of Windows XP Tablet PC Edition operating system or a derivative thereof.

<span class="mw-page-title-main">Optical trackpad</span>

An optical trackpad is an input device based on an optical sensor, which detects the displacement of a finger that is moving on top of it. The sensor is used typically in smartphones, where it replaces the D-pad, and in ultra-portable or ultra-mobile PCs, where it replaces touchpads, pointing sticks or trackballs as pointing device.

References

  1. ↑ "VersaPad Plus resistive touchpads target medical, rugged environments". www.microcontrollertips.com. Retrieved 2021-07-06.
  2. ↑ "Tap and drag". Apple.com.
  3. 1 2 "The Tactile Touchpad". sigchi.com. Archived from the original on 2011-10-01. Retrieved 2011-03-21.
  4. 1 2 "A Comparison of Three Selection Techniques for Touchpads" (PDF). yorku.ca.
  5. ↑ "Libinput features: Clickpad software button behavior". wayland.freedesktop.org.
  6. ↑ Getting Started With Your DOMAIN System. Apollo Computer. 1983.
  7. ↑ "Briefcase computer". Design. November 1983. p. 20. Retrieved 16 March 2022. The Gavilan portable computer uses a touch-sensitive panel between its text-entry keyboard and its liquid-crystal display. Moving your finger around on this shifts the cursor on the screen to select commands from a menu.
  8. ↑ "GUIdebook Psion MC Series brochure". guidebookgallery.org.
  9. ↑ "GUIdebook Psion MC Series brochure, page 4". guidebookgallery.org.
  10. ↑ Booth, Neil (2 December 1989). "Psions of the Times". New Computer Express. pp. 66–67. Retrieved 20 March 2022. You put your finger on a small rectangular panel, and the cursor appears on screen. Move your finger around the panel, say from the bottom left of the panel to the centre, and the cursor moves from the bottom left to the centre of the screen in parallel.
  11. ↑ "Olivetti S20, D33 and identically Triumph-Adler Walkstation 386, Walkstation 386SX". Archived from the original on 2016-03-04. Retrieved 2015-10-26.
  12. 1 2 3 Diehl, Stanford; Lennon, Anthony J.; McDonough, John (Oct 1995). "Touchpads to Navigate By" (PDF). Byte . No. October 1995. Green Publishing. p. 150. ISSN   0360-5280.
  13. ↑ "[Products | Our Technology | High-Sensitivity Capacitive Technology] Alps Alpine – Electronic Components and Automotive Infotainment". tech.alpsalpine.com. Retrieved 2021-07-06.
  14. ↑ Thryft, Ann R. "More Than a Mouse," Computer Product Development, EBN Extra, November 14, 1994, pp. E16 – E20
  15. ↑ "Blackbird: The PowerBook 500 Series". Low End Mac. 1994-05-16. Retrieved 2017-07-09.
  16. ↑ "MacBook design". Apple.com.
  17. ↑ Ackerman, Dan (June 10, 2009). "Apple MacBook Pro Summer 2009 (Core 2 Duo 2.26 GHz, 2GB RAM, 160GB HDD, Nvidia GeForce 9400M, 13-inch)". CNET . Retrieved April 11, 2010.
  18. ↑ "A WinBook for the Fussy". Windows Magazine. No. Dec 95. 1995. p. 105.
  19. ↑ "Sharp Unveils Line of Notebooks". Westchester County Business Journal (November 20, 1995). 1995.
  20. ↑ Malloy, Rich; Crabb, Don (October 1995). "Power Packed Power Books". Mobile Office (October 1995). New York, NY: 44–52.
  21. ↑ Jerome, Marty (1995). "Lightweight, Low-Cost Challenger". PC Computing (December 1995): 96.
  22. ↑ Yu, Justin. "This Logitech keyboard and touch pad would like the full attention of your hands". CNET. Retrieved 2021-07-06.
  23. ↑ GmbH, Systec & Solutions. "Medical keyboard and stainless steel tablet". www.systec-solutions.com. Retrieved 2021-07-06.
  24. ↑ "Analog Devices' Capacitive Shunt Method" (PDF). analog.com.
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