There are many reasons one would want to write something on a computer screen. Like marking subjects on video while making a stop-motion sequence. Currently people who need to mark up their screens have to use a regular dry erase marker, and buy a cheap monitor they don't care about.

A pen meant for writing on your computer screen would need to have a soft tip, and an erasable ink which would not be too acidic to damage the screen or leave oils behind. I'm thinking very fine charcoal powder mixed with alcohol to keep it liquid in the pen. After you write on the screen the alcohol dries and leaves the charcoal behind, hopefully sticking.

Note: this is not an idea for an input device, like a tablet pc or something, this is for writing stuff on top of a normal monitor without causing any damage (and being able to erase it).
-- DIYMatt, Aug 13 2009

Software Screen Overlay Software_20Screen_20Overlay
[xaviergisz, Aug 13 2009]

Screen Protector Film http://www.myshoppi..._Laptop_Accessories
alternative solution to the problem [xaviergisz, Aug 13 2009]

LCD Whiteboard LCD_20Whiteboard
[phoenix, Aug 13 2009]

ooh good luck with that: many people put an anti-reflective coating on that will probably get buggered up no matter what kind of ink you use.
-- FlyingToaster, Aug 13 2009


Using a whiteboard as a projector screen is an effective way to accomplish this.
-- ed, Aug 13 2009


"Note: this is not an idea for an input device..."
Then can we have a category check, please?
-- phoenix, Aug 13 2009


It's more of an onput device.

Reminds me of the joke, how can you tell if a blonde's been using the computer? Because there's tip-ex on the screen.

(Hey, I never said it was a good joke, this just reminds me of it.)
-- theleopard, Aug 13 2009



random, halfbakery