A teleprompter is a display device that prompts the person speaking with an electronic visual text of a speech or script. Using a teleprompter is similar to the practice of using cue cards. The screen is in front of the lens of the camera, and the words on the screen are reflected to the eyes of the speaker using a one-way mirror (Note that this is only true in principle - when the space behind the lens is covered in a shroud, an ordinary glass pane will work as a one way mirror). As the speaker does not need to look down to consult written notes, he or she appears to have memorized the speech or be speaking spontaneously, and will look directly into the camera lens. Cue cards, on the other hand, will always be placed away from the lens axis, making the speaker look at a point beside the camera, which leaves a "distracted" impression.
The first "Teleprompters" were simply mechanical devices located near the camera. The script was printed on a paper scroll, which was advanced as the performer read.
The TelePrompTer Company was founded in the 1950s by Fred Barton Jr., Hubert J. (Hub) Schlafly and Irving Berlin Kahn. Barton was an actor who suggested the concept of the teleprompter as a means of assisting television performers who had to memorize large amounts of material in a short time.
The First Personal Computer based Teleprompter, Compu=Prompt appeared in 1982. It was invented and marketed by Courtney M. Goodin & Laurence B. Abrams in Hollywood, California. This custom software and specially re-designed camera hardware ran on the ATARI 800 Personal Computer. Their company later became ProPrompt Inc., which is still providing teleprompting services some 23 years later. Other Paper-based Teleprompting Companies Q-TV and Telescript followed suit and developed their own software several years later when the Commodore 64 the IBM PC evolved into computers with enough graphics power to provide the smooth scrolling text.
It should also be noted that Jess Oppenheimer, producer of "I Love Lucy", rightfully claims credit for the original concept of the teleprompter and was awarded the U.S. patent for its creation. Used for Lucille Ball to read commercials on-camera, it soon became the staple for the newscast industry.
Modern Teleprompters for news programs consist of a personal computer, connected to video monitors on each camera. The monitors are often black-and-white monochrome, and have the horizontal scanning reversed to compensate for the reflection of the mirror. A peripheral device attached to the serial port has a knob that can be turned to speed up or slow down the scrolling of the text. The text is usually displayed in white capital letters on a black background for the best readability, while cues are in inverse video (black on white). Difficult words (mainly foreign names) are spelled out phonetically, as are other particulars like "2-thousand-8" (to specify that the year 2008 should not be pronounced "twenty-oh-eight", for example).
Teleprompters are often used for speeches as well. In this application they are called Conference Teleprompter Systems. In this case, the reflector is usually a piece of glass with a special partially reflective coating. It is mostly transparent so as not to block the view of the speaker by the audience or cameras. Usually two of these are set up, one on either side of the podium (if there is one), so the speaker can look around at the audience and always be able to see one. Except for these aesthetic changes, they work the same as for television. When used in this configuration the unit is often, in the USA, called presidential glass due to its association with speeches made by the President of the United States.
Teleprompters are sometimes used in concerts, to assist performers who have trouble remembering the words to songs. The teleprompter may be of the kind used in speeches, or may just be a monitor set into the stage floor. Notable singers who have regularly used Teleprompters during concerts include Frank Sinatra, Bruce Springsteen, Elton John, and Bernard Sumner of New Order.