What is Light Pen?

Ø  A light pen may be a computer data input device within the sort of a light-sensitive wand utilized in conjunction with a computer's CRT (CRT) display.

Ø  Used with a CRT monitor, these devices were an early sort of manipulating and highlighting data on the screen. In the picture is an example of a lady employing a electronic stylus to spotlight text on the screen?

Ø  Light pens were originally developed around

Ø  1955 and in the 1960s, they became more commonly used with graphics terminals, like the IBM 2250. In the 1980s, electronic stylus usage expanded to home computers, just like the BBC Micro computer. Some graphics cards also included a connection for a light-weight pen. Today, light pens are not any longer used thanks to the invention of touch screens.

Ø  The term light pen may also refer to a pointing input device utilizing a light that is commonly used during a presentation. The light pen are often a really focused flashlight-type of device or a laser pointer, allowing a user to direct viewers' attention to a selected area, sort of a picture or text, in the presentation.

Ø  A light pen may also be used to describe the pen (stylus) used with a graphics tablet.

Ø  Light pen allows the user to display objects and draw on the screen in a similar way to touch screen. Light pen can work with Cathode Ray Tube based display.It also used with LCD display.It detects changes in brightness of screen pixels when scanned. Light pen scanned by cathode ray tube electron beam and communicates the timing.

Ø  Light pen first time created in year 1955. In year 1960 light pens were common on graphics terminals.

Ø  The light pen works with CRT monitors. It considered as the predecessor to touchscreen technology. It also became popular during the 1980s for home computer. It works by detecting the change in brightness of nearby pixels, which indicates that the CRT's electron beam is scanning in that area,

Ø  Light pen also known as  pointing input device utilizing a light that is commonly used during a presentation.

Ø  The light pen has a photo sensor  at the tip that responds to the peak illumination that occurs when the CRT scanning spot passes its point of focus. First time light pen was used to draw items with the aid of a tracking cross.

Ø  It was moved across the screen, the part of the tracking cross sensed changes thus allowing the direction of movement of the light pen to be ascertained.

Ø  Pen computing refers to any computer user interface using a pen and tablet, input devices such as keyboard or a mouse. It has a photocell and an optical system placed in a small tube.

Ø  Its tip is moved over the screen and pen button pressed then its photocell sensing  element detects the screen location and sends signals to the central processing unit.

Ø  Light pen may be used as input device. It is used as a pick device with graphics system.

Ø  There are different types of light pens:

Corded light pens, Battery light pens, Design pen, Tablets, LED light pen,