25-06-2019 | | By Moe Long
Projectors aren’t exactly new. Existing in a variety of forms, from 35mm film projectors to slide projectors, and even overhead projectors, these devices offer a means of casting a large image on virtually any surface. Digital projectors come in a variety of forms, and with increasingly affordable projectors, have seen additional adoption outside of classrooms, theatres, and conference rooms. But like panel televisions which range from LCD and LED to plasma, projectors utilize different projection technology. Learn about DLP vs LCD vs LED in projectors!
In the world of digital projection, there are four main projector technologies: DLP, LCD, LED, and LCOS. DLP stands for Digital Light Processing which employs a chip comprised of microscopic mirrors and a spinning color wheel to generate an image. LCD projectors opt for liquid crystal displays rather than physical moving parts as you’ll find in DLP projectors. LED projectors, or light emitting diode projectors, are a bit of a different breed. These are either DLP or LCD technologies, but tout LED light sources. LCoS on the other hand stands for liquid crystal on silicon and is a sort of DLP-LCD hybrid which uses liquid crystal chips and a mirrored backing. Then, there are laser projectors which differ from lamp-based projectors by opting for a solid state laser rather than a lamp for its light source.
Image source: en.wikipedia.org
A DLP, or digital light processing, projector makes use of tiny mirrors which in turn reflect light toward a screen. There’s typically a physical color wheel, which is a literal spinning wheel full of color filters used to generate sequential colors. These can be found as single-chip DLP projectors, or three-chip DLP projectors with red, green, and blue DLP chips. Price varies quite a bit, from a couple hundred dollar to ten of thousands. DLP projector are easily the most common, with the vast majority of home theatre projector utilizing DLP technology.
Light output on DLP projectors tends to be robust, and suitable for atmospheres with ambient light such as classrooms and conference rooms. Likewise, color accuracy, while varying quite a bit by device, oftens shines with DLP projectors. Motion blur isn’t a huge issue on most DLP projectors, with crisp, sharp images during fast-motion sequences in action flicks and sports. However, DLP projectors may be plagued with rainbow artifacts where bright objects may give off the appearance of a sort of light trail. This doesn’t affect three-chip DLP projectors, but single-chip DLP projectors might experience artifacting.
Image source: en.wikipedia.org
While LCD, or liquid crystal display, technology is common in TVs and computer monitors, it’s also popular in the projection space. LCD projectors feature three LCD panels which in turn cast an image using a primary color: red, blue, and green. All three are simultaneously projected so that the resulting image is displayed in its full coloring. Price varies quite a bit, from a few hundred to the upper thousand.
Generally, LCD projectors are pretty inexpensive to operate since they eschew moving parts. Lamp life is generally much higher than with DLP projectors. Color accuracy is top-notch, and there’s pretty low power consumption. Black levels shine, and light output or lumens can be pretty high. Rainbow artifacts are kept to a minimum, though motion blur may be an issue.
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LED is a common term in lighting technology, standing for light-emitting diode. Whereas DLP and LCD projectors refer to projection technology, LED concentrates on light source. In fact, LED projectors may use DLP or LCD technology. But rather than a traditional lamp, LED projectors instead use high efficiency bulbs which substantially increase lamp life. As opposed to the 1,000-5,000 hour lamp life of most projectors, LED projectors instead boast upwards of 20,000 hours. Like LCD and DLP projectors, these can be incredibly inexpensive or bank account-emptying. Black levels, motion blur, color accuracy, and artifacting depends on the underlying projection source, DLP vs LCD. However, maintenance of LED projectors minimizes overhead since there’s a filterless design, and long lamp life. My BenQ GV1 and ZTE Spro2 projectors are LED devices, making use of an LED light source and DLP projection technology.
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LCoS, or liquid crystal on silicon, arrives as a sort of LCD-DLP fusion. At its core, LCoS employs liquid crystal chips that have a reflective backing similar to DLP. However, an LCoS projector passes light through LCD panels which gets modulated by liquid crystals. Therefore, it’s at once a reflective technology and one which opts for LCDs rather than mirrors. There’s extremely high resolution, and SVGA LCoS projectors don’t even exist. Yet this comes at a cost: weight. The lightest LCoS projectors clock in a but over 10 pounds. DLP, LCD, and LED projectors are far more portable. The likes of JVC and Sony use proprietary LCoS tech, D-ILA and SXRD respectively. I’ve got a hulking Sony VPL-VW60 home theatre projector with LCoS technology onboard and, while not nearly as portable as my ZTE Spro2 or BenQ GV1, the VPL-VW60 delivers top-tier image quality with lush color reproduction and gorgeous black levels. Usually, price is a bit higher, mostly in the thousands.
There’s a reason videophiles flock to LCoS projectors, and contrast ratio, an important image quality spec, proves why. Performance is superb, and likewise black levels are incredible with deep blacks and bright whites. Light output can vary, with many older LCoS projectors offering pretty low lumens and newer LCoS sets yielding high light output. Unfortunately, motion blur, as with LCD projectors, may be an issue, though there’s almost no rainbow artifacting.
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Traditionally, lamps provide the light source for projectors. This remains true of DLP, LCD, LED, and LCoS projectors. However, lasers are beginning to replace lamps in projectors and may be the future of projection. Image quality is fantastic, arguably trouncing even LCoS, and lasers last longer than even energy-efficient LED bulbs. Moreover, lasers are more durable than traditional projector bulbs, while delivering almost instantaneous on-off functionality. Similar to an LED projector, a laser projector still uses an LCD, DLP, or LCoS chip, and speaks of the light source rather than the projection technology itself.
While a standard bulb-centric projector uses RGB lighting to reproduce colors on the screen, a laser projector instead generates the precise colors needed for a picture. As such, it’s more energy-efficient, and this even allows a laser projector to get extremely bright, far brighter than DLP, LCD, or LCoS units. Ok, so what’s the catch? Price. Laser projectors are incredibly expensive, retailing for several thousand at minimum.
Ultimately, selecting a projector depends on several factors, notably budget. DLP, LCD, and LED projectors are pretty common and vary from sub-$100 budget projectors to several thousand dollar devices. LCoS boasts videophile-caliber image quality at the expense of cost. Laser projectors present the best image available from a projector, but are too costly for mainstream adoption.