The graphics tablet or digitizer is a device that lets the user input hand drawn images, graphics, text, or hand written signatures into a computer. This device may also be used to trace an image by securing it to the face of the device and tracing it onto the tablet.
The device has a flat surface where the user draws or traces an image by using a pen-like drawing tool called a stylus. The image itself is usually not shown on the screen of the tablet, but displayed on the computer monitor instead. Some devices are used as a mouse replacement, using it as the pointing tool and navigation device for a desk top computer.
The first graphics tablet used for handwriting recognition by a computer was the Stylator, developed in 1957. Introduced in 1964 was a device called the Grafacon or RAND Tablet. It used a grid of wires under the face which encoded the horizontal and vertical coordinates into a magnetic signal, then the stylus would receive the signal and decode it.
In the mid 1970s and early 1980s, digitizers became popular and commercially successful when Summagraphics Corp. manufactured the Intelligent Digitizer (ID) and BitPad. These devices aided in the graphic designs of many Computer Aided Design (CAD) systems and bundled with PCs using CAD software.
The KoalaPad was the first home computer graphics tablet designed for the Apple II, but was expanded to work with any computer with graphics support, like the TRS-80 computer, Commodore 64 and the Atari 8-bit family. In 1981, musician Todd Rundgren developed the first color graphics tablet software for the personal computer, the Utopia Graphics Tablet System, licensed to Apple.
There are several types of tablet categories:
Passive tablets use electromagnetic technology to transmit and receive data. The Rand tablet would only transmit. These signals would enable the tablet to sense the pen without contact to the surface, and also powers the pen so it does not require batteries.
Active tablets use an internal battery stylus to transmit the signal to the tablet, which results in a bulkier pen.
Optical tablets use a small digital camera in the pen, and use pattern matching for the display.
Acoustic tablets use a small sound generator in the pen which is picked up by two microphones near the writing surface of the tablet.
Electromagnetic tablets use this signal generated by the pen and received by a grid of wires in the tablet. Some designs generate the signal in the grid of wires and are detected by the pen.
Capacitive tablets use electrostatic or capacitive signals to detect the pens location while it is hovering over the face of the tablet.
A graphics tablet offers a higher precision than a touchscreen by the ability to track an object that is not in contact with the screen. Older or less expensive tablets mainly used by children, have a wired pen similar to the RAND tablet.
An accessory for a tablet is called a puck and is the most commonly used tool. It is a mouse-like device that detects exact position and rotation. There are many styles of the puck, some are large, some small, and others contain dozens of buttons and controls. Many professionals use a puck to aid in CAD designs.
Some tablets offer embedded LCD which allows drawing directly onto the tablet itself, allowing for increased accuracy.
Wacom holds many patents for the graphics tablet technology which forces its competitors to find alternate technology or purchase a license from Wacom.
Some of the available graphics tablets are the Cintiq from Wacom, the Hitachi Starboard, the Yiynova DP10 and MSP19, the Usync PenStar, the Hanvon SenTIP, the GD Itronix Duo Touch, and the p-active XPC-1710a and XPC-1910a. There have been projects developed that combine an LCD monitor and a graphics tablet in to one device.
Using graphic tablets are a more natural way of producing graphics on the computer. It can also be used as a replacement of the mouse or keyboard. Using a tablet with an editing program such as Adobe Photoshop gives the user more precision while creating drawings.
The graphics tablet has spawned similar devices such as interactive whiteboards that are a wall sized tablets used in schools and meeting rooms. Also audio graphic tablets have been produced for the blind which offer swelled graphics on the tablet and voice feedback. This technology is called Tactile Talking Tablets or T3.
Image Caption: A Wacom Bamboo Capture graphics tablet with stylus. Credit: DragonLord/Wikipedia (CC BY-SA 3.0)