Display technology

See also: Liquid crystal display television

Thanks to the advances in display technology, there are now several kinds of video displays used in modern TV sets:
CRT (cathode-ray tube): The most common screens were direct-view CRTs for up to roughly 100 cm (40 inch) (in 4:3 ratio) and 115 cm (45 inch) ((in 16:9 ratio) diagonals. These are the least expensive, and are a refined technology that can still provide the best overall picture quality value. As they do not have a fixed native resolution, they are capable of displaying sources with different resolutions at the best possible image quality. The frame rate or refresh rate of a typical NTSC format CRT TV is 29.97 Hz, and for the PAL format, 25 Hz, both are scanned with two fields per frame in an interlaced fashion. A typical NTSC broadcast signal's visible portion has an equivalent resolution of about 640x480 pixels. It actually could be slightly higher than that, but the vertical blanking interval (VBI), allows other signals to be carried along with the broadcast. High lead content.
Rear projection: Most very large screen TVs (to 100 inches [254 cm] or more) use projection technology. Three types of projection systems are used in projection TVs: CRT-based, LCD-based, and DLP (reflective micromirror chip) -based. Projection television has been commercially available since the 1970s, but at that time could not match the image sharpness of the CRT; current models are vastly improved, and offer a cost-effective large-screen display.
A variation is a video projector, using similar technology, which projects onto a screen.
A modern Philips LCD TV
Flat panel (LCD or plasma): Modern advances have brought flat panels to TV that use active matrix LCD or plasma display technology. Flat panel LCDs and plasma displays are as little as 25.4 mm (1 inch) thick and can be hung on a wall like a picture or put over a pedestal. Some models can also be used as computer monitors.
LED technology has become one of the choices for outdoor video and stadium uses, since the advent of bright LEDs and driver circuits. LEDs enable scalable ultra-large flat panel video displays that other technologies may never be able to match in performance.

Each has its pros and cons. Flat panel LCD display can have narrow viewing angles and so may not suit a home environment. Rear projection screens do not perform well in daylight or well-lit rooms and so are only suited to darker viewing areas. A comparison of these technologies is available here.