Light-pens... The principle behid this device is perfectly understandable and simple (ingenious even).
Picture on regular monitors (Cathode Ray Tube monitors (CRT)) is formed in series of horizontal lines that stream over and over again many times in a second across the whole front surface of the screen. Light-pen is a pointing device that senses the light from the ray forming those lines on a monitor; it senses light ray at a certan time since the ray started its path, and acording to that time it calculates and determines where you placed the pen on screen at that point in time - that information is sent back to computer and it places the cursor at that coordinate.
I can't seem to find much information about light-pens on web, which means that it isn't used very much. WHY?
Is it too inacurate? (theory is one, practise is something else - maybe that mechaism has flaws)
If not - then I can't understand it (can't imagine some other reason not to put it in the widest use (...except legal ones...)) - because light pens are the most natural way to point on screen (especially if you have a hole in a desk and you place your monitor in it, so you draw on it like on a paper).
Why isn't it used!?!
Can someone explain this phenomenon?
(maybe someone had an opportunty to use it - share your expirience - is light-pen worth it if you plan to use it to draw stuff (light-pen mind you, not touch-screen with a pen))