The large display reproduces information in such a way that it is also clearly visible from greater distances. Examples of easily recognizable large displays are the displays for the current driving speed of motor vehicles in the vicinity of kindergartens and primary schools, the constantly updated digital displays for arrival and departure times with train designation, direction and platform information at train stations, displays of the energy yield from solar systems public buildings, the display of the available parking spaces in various parking garages and parking spaces in heavily frequented city centers and the counter displays for the current occupancy of an individual parking garage. 
A large display can therefore show measurement results or information, but for some purposes also warnings or instructions such as "STOP" or "PLEASE WAIT".
With the devices that display measured values, a distinction can be made between independent devices with built-in or externally connected sensors and those that receive the data from other measuring devices or from a computer as the sole or additional display. A large display that records and processes the measured values directly from internal or external sensors can be designed in such a way that it only recognizes certain sensor types and displays their physical measured variables. Depending on the application, other types of large display can be configured for different sensor types and measuring ranges and thus adapted to other measured variables if required.
Influences on the visibility of a large display
Character height, lighting and contrast all affect the distance from which information can be reliably read. A digital display board is usually only referred to as a large display if the individual characters displayed are more than 50 mm high. The size of the display area and the dimensions of the individual characters determine how many characters can be displayed on the large display at the same time. There are both single-line and multi-line display variants. In addition to the height of the characters and the ability of the viewer to see, the contrast of the characters displayed to the background determines how far they can be seen. The lighting conditions and whether the large display is to be read from the front or from different angles must also be taken into account when making the selection. There are variants with different colors for the characters and for the background and ultra-bright luminous models especially for devices that need to be readable outside in sunlight. Special displays can adjust their brightness to changing light conditions.
Content that can be displayed with different types of large digital displays 
The large displays differ, among other things, in the options for displaying characters they offer. The number of characters that can be displayed on the large display is specified as 4 x 20, for example, which means that twenty characters can be displayed in four lines each. There are simple variants that only show digits and characters as a 7-segment display like on a simple pocket calculator without a graphic function. A one-line large display with 7 segments is available, for example, with space for 1 to 12 digits, with or without the option of displaying a period or colon between the digits. It is often used when it comes to displaying only a variable number with or without the same unit. The unit then does not have to be made visible electronically, but the lettering is usually applied firmly to the surface of the large display using a coating process. Examples of measured variables that are displayed in this way include the time, temperature, relative humidity, weight, speed, speed or sound level.
If alphanumeric characters are to be displayed on the large display that cannot be displayed using such a 7-segment display, displays with 38 or 54 segments or with a dot matrix can be selected. If the rectangle for the representation of a character is broken down into individually controllable pixels on a large display, then these individual pixels are arranged in regular horizontal and vertical rows - a dot matrix. Such displays usually have a pre-programmed character set with numbers, letters and symbols. In the case of graphics-capable displays, the display area of the large display is used in whole or in part for images and graphics made up of individual points.
