Editing Digital light processing (section)

=== Light source ===
[[File:InFocus IN34.jpg|thumb|right|220px|The InFocus IN34, a DLP projector]]
DLP technology is independent of the light-source and as such can be used effectively with a variety of light sources.  Historically, the main light source used on DLP display systems has been a replaceable high-pressure [[xenon arc lamp]] unit (containing a quartz arc tube, reflector, electrical connections, and sometimes a quartz/glass shield), whereas most pico category (ultra-small) DLP projectors use high-power LEDs or [[laser]]s as a source of illumination.
Since 2021 a laser light source has become very common on many professional projectors, for example the Panasonic PT-RZ990.<ref>{{cite web | url=https://business.panasonic.co.uk/visual-system/rz990-series-compact-and-flexible-1-chip-dlp-projectors | title=PT-RZ990 SERIES - Compact and Flexible 1-Chip DLP™ Projectors - Visual System Solutions &#124; Panasonic Business }}</ref>

==== Xenon arc lamps ====
For [[xenon arc lamp]]s, a constant-current supply is used, which starts with a sufficiently high open-circuit voltage (between 5 and 20&nbsp;kV, depending on lamp) to cause an arc to strike between the electrodes, and once the arc is established, the voltage across the lamp drops to a given value (typically 20 to 50 volts<ref name="superior">{{cite web |title=Xenon Short Arc Lamps |url=https://www.sqpuv.com/PDFs/TechnicalSpecificationGuide.pdf |website=www.sqpuv.com |publisher=Superior Quartz Products |access-date=5 October 2021}}</ref>) while the current increases to a level required to maintain the arc at optimal brightness. As the lamp ages, its efficiency declines, due to electrode wear, resulting in a reduction in visible light and an increase in the amount of waste heat. The lamp's end of life is typically indicated by an LED on the unit or an onscreen text warning, necessitating replacement of the lamp unit.

Continued operation of the lamp past its rated lifespan may result in a further decrease in efficiency, the [[lightcast]] may become uneven, and the lamp may eventually become hot enough to the point that the power wires can melt off the lamp terminals. Eventually, the required start-up voltage will also rise to the point where ignition can no longer occur. Secondary protections such as a temperature monitor may shut down the projector, but a thermally over-stressed quartz arc tube can also crack or explode. Practically all lamp housings contain heat-resistant barriers (in addition to those on the lamp unit itself) to prevent the red-hot quartz fragments from leaving the area.

==== LED-based DLPs ====
The first commercially available LED-based DLP HDTV was the [[Samsung]] HL-S5679W in 2006, which also eliminated the use of a color wheel. Besides long lifetime eliminating the need for lamp replacement and elimination of the color wheel, other advantages of LED illumination include instant-on operation and improved color, with increased color saturation and improved color gamut to over 140% of the [[RGB color space|NTSC color gamut]]. Samsung expanded the LED model line-up in 2007 with products available in 50-, 56- and 61-inch screen sizes. In 2008, the third generation of Samsung LED DLP products were available in 61- (HL61A750) and 67-inch (HL67A750) screen sizes.

Ordinary LED technology does not produce the intensity and high-lumen output characteristics required to replace arc lamps. The special LEDs used in all of the Samsung DLP TVs are [[PhlatLight]] LEDs, designed and manufactured by US-based [[Luminus Devices]]. A single RGB PhlatLight LED chipset illuminates these projection TVs. The PhlatLight LEDs are also used in a new class of ultra-compact DLP front projector commonly referred to as a "pocket projector" and have been introduced in new models from LG Electronics (HS101), Samsung (SP-P400) and [[Casio]] (XJ-A series). Home theater projectors will be the next category of DLP projectors that will use PhlatLight LED technology. At InfoComm in June 2008, Luminus and TI announced their collaboration on using their technology on home theater and business projectors and demonstrated a prototype PhlatLight LED-based DLP home theater front projector. They also announced products will be available in the marketplace later in 2008 from [[Optoma Corporation|Optoma]] and other companies to be named later in the year.

Luminus Devices PhlatLight LEDs were also used by [[Christie (audiovisual company)|Christie Digital]] in their DLP-based [[MicroTiles]] display system.<ref>{{cite press release| url = http://www.businesswire.com/portal/site/home/permalink/?ndmViewId=news_view&newsId=20100609006222&newsLang=en |archive-url=https://web.archive.org/web/20120919143312/https://www.businesswire.com/portal/site/home/permalink/?ndmViewId=news_view&newsId=20100609006222&newsLang=en |archive-date= 2012-09-19 |title=Luminus Devices' PhlatLight LEDs Illuminate Christie MicroTile's New Digital Canvas Display |via=Businesswire |date=June 9, 2010}}</ref> It is a modular system built from small (20&nbsp;inch diagonal) rear projection cubes, which can be stacked and tiled together to form large display canvasses with very small seams. The scale and shape of the display can have any size, only constrained by practical limits.

==== Laser-based DLPs ====
The first commercially available laser-based DLP HDTV was the [[Mitsubishi]] L65-A90 LaserVue in 2008, which also eliminated the use of a color wheel. Three separate color lasers illuminate the [[digital micromirror device]] (DMD) in these projection TVs, producing a richer, more vibrant color palette than other methods. See the [[laser video display]] article for more information.