LCARS screens, as seen in Star Trek Nemesis
|Plot element from the Star Trek franchise|
|First appearance||Star Trek: The Next Generation|
|Created by||Michael Okuda|
|Type||Computer operating system|
In the Star Trek fictional universe, LCARS (//; an acronym for Library Computer Access/Retrieval System) is a computer operating system. Within Star Trek chronology, the term was first used in the Star Trek: The Next Generation series.
The LCARS graphical user interface was designed by scenic art supervisor and technical consultant Michael Okuda. The original design concept was influenced by a request from Gene Roddenberry that the instrument panels not have a great deal of activity on them. This minimalized look was designed to give a sense that the technology was much more advanced than in the original Star Trek. The early display panels were made out of colored Plexiglas with light behind them, a technique that can produce complex-looking displays cheaply. As the show progressed, use of animations increased. Most were displayed on video equipment built into the sets.
When Michael Okuda was asked about the design of the LCARS display, he responded "I came up with the LCARS style in part because of Gene Roddenberry's directive that he wanted his new Enterprise to be so advanced that it looked simple and clean. The other part of the LCARS style was that it had to be something that could be manufactured quickly and easily on a television budget."
In the Star Trek franchise, the LCARS interface is often seen used on a PADD (Portable Auxiliary Data Display), a hand-held computer. 
PADDs of various designs are used in the Star Trek universe by such space-faring organizations as Starfleet, the Andorian Imperial Guard, Bajoran Militia, Cardassian Union, Klingon Empire, Romulan Star Empire and Vulcan High Command. They are common to cultures even as distant as the Delta Quadrant.
At 7 inches (18 cm), similarly sized modern tablets such as the Nexus 7, Kindle Fire, Blackberry Playbook as well as the iPad mini have been compared with the PADD. Several LCARS style apps are available which offer an LCARS-style interface.
CBS Studios Inc. claims to hold the copyright on LCARS. Google was sent a DMCA letter to remove the Android app called tricorder since its use of the LCARS interface was un-licensed. The application was later re-uploaded under a different title, but it was removed again.
- Star Trek: The Next Generation Technical Manual
- Star Trek: The Magazine, Issue 7, November 1999
- Make It So: What Star Trek Tells Us About How to Make Tablets, The Atlantic
- How Star Trek artists imagined the iPad... 23 years ago, Ars technica
- New ‘LCARS’ iPad Application Released, TrekMovie.com
- Make It So: Hands-On With Official Star Trek iPad App, Ryan Paul, Wired, July 16, 2011
- Tricorder - Android Projects by Moonblink - Google Project Hosting, archived from the original on 2012-10-27, retrieved 2014-04-18
|Wikimedia Commons has media related to LCARS.|