A display device is a device that presents information for visual or tactile reception or for acquiring, storing or transmitting the information in various forms. When the input to the display device is provided in the form of an electrical signal then such a display device is called an electronic display device. Generally, electronic display devices present the information in a visual or tactile form.



The most common application of tactile device is for providing information to the blind or visually impaired person. Such an electronic display device uses electro-mechanical parts to dynamically update a tactile image, which is generally is in the text form, so that the image could be felt by running the fingers on it.

The electronic display devices are of two types: analog and digital.

Initially the electronic display devices were available only in the analog form. The best example of such a device is cathode ray tube or CRT in short. This device is an evacuated glass envelope that contains an electron gun and a fluorescent screen usually with the provision of internal or external means to accelerate or deflect the electrons. The electron gun is a source of electrons and when these electrons strike the fluorescent screen, light is emitted. The electron beams are deflected and modulated in such a way that an image is displayed on the screen. This image could represent electrical waveforms as in oscilloscope, pictures as in television or computer monitor or as a screen of radar.

Digital electronic display devices were developed later. A list of some of the digital display devices are given below:

1. Bistable display

2. Electronic paper

3. Nixie tube displays

4. VF display

5. LED display

6. ELD

7. Plasma display panels (PDP)

8. Liquid crystal display (LCD)

There are many more digital electronic display devices that are being developed each day.

The "Check Engine" light on automobile dashboard is a good example of a type of electronic display device that is known as "idiot light". This light only gives the information that there is some problem with engine but no farther details is provided to help solve the problem and also regarding the urgency of the problem.

Some electronic display devices only display digits or alphanumeric characters. These devices are called segment displays, because the display consists of several segments that switch on or off to give the appearance of any desired character ("glyph").

Presently, most of the displays used in any industry are electronic display device that display different parameters of the process as well as any error encountered to enable the operators to rectify the problem.