digitizing tablet
A graphics tablet or digitizing tablet is a flat rectangular input device for vector coordinate points. It is used for the manual conversion of painted, drawn or constructed supervisory templates in order to enter them into the computer. Likewise, graphics tablets are used as creative painting tools. Coordinate points are captured by a pen, stylus or puck that is moved across the tablet. The cursor on the screen always follows the pen position, and the pen tip can be moved up to one centimeter above the tablet.
Various techniques are used with the graphics tablet. When determining the position, a distinction is made between methods using ultrasound, inductive, magneto-mechanical and positiometric methods.
The best-known method, which has a high degree of accuracy and resolution, is the inductive method. In this method, the graphics tablet consists of many thin wires stretched vertically and horizontally to form a wire grid. Pulses are sent through the wires one after the other, at a frequency between 200 Hz and 500 Hz. When the pulses hit the activated pin, which detects induced voltages, the pin sends a signal to the computer, which uses it to calculate the position of the pin.
The pens can be wired, cordless and battery-free; they can also be pressure- and tilt-sensitive. For example, there are pen designs that distinguish 1,024 pressure levels and whose tilt angle is used for pen identification.
The sizes for graphic tablets depend on the application and range from DIN A6 to DIN A3; the resolution is between a few hundred dpi and about 5,000 dpi, depending on the process. Their field of application is mainly in the constructive area.