Electronic paper, e-paper and electronic ink are display technologies which are designed to mimic
the appearance of ordinary ink on paper. Electronic paper displays reflect light like ordinary paper,
theoretically making it more comfortable to read, and giving the surface a wider viewing angle compared to
conventional displays. The contrast ratio in available displays as of 2008 might be described as similar to
that of newspaper, though newly developed displays are slightly better. An ideal e-paper display can be
read in direct sunlight without the image appearing to fade.
Many electronic paper technologies can hold static text and images indefinitely without using electricity. Flexible
electronic paper uses plastic substrates and plastic electronics for the display backplane. There is ongoing
competition among manufacturers to provide full-color ability.
A plasma display panel (PDP) is a type of flat panel display common to large TV displays 30 inches
(76 cm) or larger. They are called "plasma" displays because the technology utilizes small cells containing
electrically charged ionized gases, or what are in essence chambers more commonly known as fluorescent
Speech output might include speech synthesis, headphones or speakers
Speech synthesis is the artificial production of human speech. A computer system used for this purpose
is called a speech synthesizer, and can be implemented in software or hardware products. A text-tospeech (TTS) system converts normal language text into speech; other systems render symbolic
linguistic representations like phonetic transcriptions into speech.