Tablet Computers, a single-panel computer that can be used for a variety of tasks.
The usage of a touch screen as an input device is its distinctive feature.
Modern tablets are operated with the fingers, with the option of using a stylus, whereas older tablets needed the use of a stylus.
iPad, Android, BlackBerry, and Windows:
After years of mixed success with other vendors’ tablets, Apple’s iPad launched in 2010, igniting a tablet revolution on par with the iPhone’s.
Android tablets have given the iPad a run for its money with numerous models from several vendors.
BlackBerry maker Research In Motion (RIM) introduced the PlayBook to entice existing customers.
See iPad, Android, and BlackBerry Playbook.
Windows tablets have had an erratic history, appearing from time to time and disappearing,
Windows 8 is expected to change the game (see Windows 8 and Tablet PC).
Thousands of Apps
All tablets come with a Web browser and a variety of apps.
Additional applications are available from the vendor’s online store.
For example, iPad apps come from Apple’s iTunes store. Android apps are available from Google Play (formerly Android Market),
And Amazon has its app store for the Android-based Fire (see Kindle Fire).
Definition of Tablet PC
(1) Lower case “t” tablet PC:
Any tablet computer, including non-Windows models. See tablet computer and iPad.
(2) Upper case “T” Tablet PC:
A Windows tablet computer environment from Microsoft.
Introduced when Windows XP was the latest Windows OS, the Tablet PC was designed to function as a portable writing tablet.
It includes handwriting recognition as well as the ability to retain handwritten words and annotations without turning them into text.
This “rich digital ink” capability stores the writing or drawing as a graphic after algorithms smooth out rough edges.
See touch screen, Ultra-Mobile PC, and tablet computer.
Do You Know About Touch Screen?
A touch-sensitive display screen that responds to the touch of a finger or stylus.
After Apple debuted the iPhone in 2007, the touch screen became incredibly popular on handhelds.
It was widely utilized on ATMs, retail point-of-sale terminals, automotive navigation systems, hospital monitors, and industrial control panels.
In comparison to a fixed set of physical buttons, touch screens have various advantages.
The most important of which is the endless ways the user interface can be built and updated.
If there is no hardware keyboard on the unit, a “soft” keyboard can be displayed on-screen whenever text must be typed in.
Touch displays may also take handwriting, graphics, and finger movements in addition to hand printing and handwriting (see multitouch).
In comparison to regular computer screens, touch screens may be engineered to withstand severe situations.
All touch screens “digitize” the point of contact on the screen into an X-Y coordinate.
There are two types of touch screens:
Active digitizer and Passive touch screen.
What Are Active Digitizer Tablets?
Even though graphics tablets have long been utilized in CAD and other graphics applications, digitizer technology was embedded behind the screen of tablet PCs to operate the computer with the precision of a mouse.
An electromagnetic signal is transmitted to an X-Y grid with a high resolution using a stylus.
The stylus can be self-powered by being hooked to the unit or by using a small battery,
Or it may obtain its power from the tablet surface, which alternates between transmitting and receiving.
Tablet PCs can use both active digitizer and passive touch screen technology, providing precision with a stylus and simplicity with a finger.
See digitizer tablet for further information.
Passive Touch Screens
Pressure-sensitive resistive screens can be touched with a finger, stylus, or almost any pointed object.
They use two active layers, with insulated spacers in between a flexible plastic layer on top of a stiff plastic or glass layer.
Different voltages are applied across the coatings, often alternating across the layers, and the layers are coated with indium tin oxide.
When the front layer is contacted, the rear layer detects the voltage from the rear,
And the front layer detects the voltage from the back, allowing the controller to identify the X-Y location.
Because of the many layers and coatings,
The resistive approach blocks up to 30% of the light from the CRT or LCD screen, despite being the least cost.
The capacitive method uses only one active layer: a metallic coated glass panel, thus allowing more light to come through.
When a finger touches the screen, voltage is supplied to the corners, and a little quantity of current is drawn.
The controller computes the X-Y location from the change in capacitance caused by that touchpoint.
Because the human body absorbs current, the finger must be used and not a plastic stylus.
This method is also commonly used by touchpads on laptops.
A sensor grid is layered between two glass layers in a version known as “projected capacitive.”
When the screen is touched, the controller uses the change in capacitance in the grid to calculate the X-Y location.
The grid also enables two-finger touching like Apple’s multitouch iPhone.
Although the grid is embedded and protected, the screen can be overlaid with a clear, heavy-duty glass layer for more protection. See multitouch.
Acoustic Waves and Infrared
From the top and side, acoustic waves or infrared signals are delivered across the screen’s external surface.
When the screen is touched, the receivers on both ends build an X-Y matrix and detect the obstructed signals.
These approaches do not block any light because they do not utilize active layers over the screen.
For added protection, the screens can be covered with a clear, heavy-duty glass covering.
Definition of: Digitizer Tablet
Sketching new images or tracing old ones is done with a graphics drawing tablet.
A wired or wireless pen or puck is used to contact the device’s surface, sometimes known as a “graphics tablet.”
The puck, which is commonly referred to as a mouse, is the “tablet cursor.”
The pen or the puck are both used for sketching. For tracing, the puck is preferred because its crosshairs, visible through a clear glass lens, lets you precisely pinpoint the ends and corners of detailed drawings.
Most tablets allow users to turn areas of the tablet’s surface into buttons that may be pressed to access menus and functionalities within the app.
Mouse Mode and Digitizer Mode
Tablet computers usually have two modes of operation.
The “Digitizer mode” establishes a one-to-one correlation between the tablet and the display.
Wherever you make contact on the tablet is the exact location on-screen that is affected.
Like a mouse, “mouse mode” moves the screen pointer to any starting place on the tablet surface.
X-Y Coordinates are the output.
When drawing or tracing on the tablet, a series of x-y coordinates (vector graphics) are created,
Either as a continuous stream of coordinates or as endpoints. See pen tablet, tablet PC, and touch screen.
Definition of: Pen Tablet
A digitizer tablet that is specialized for handwriting and hand marking. LCD-based tablets emulate the flow of ink as the tip touches the surface and pressure is applied.
On non-display tablets, handwriting is displayed on a second computer screen.
See also digitizer tablet and tablet computer.