PAL DLP TVs

The two relatively new technologies, Plasma and Digital Light Processing (DLP), have begun to give a tough competition for their respective market shares of high resolution TV market. In spite of similar customer base, these two state-of-the-art technologies differ widely in the way they process light-source information. In the same manner, LCD and DLP refer to two different set of technologies. Question is which one is better?

Toshiba 52" DLP Projection TV 52JM9UE

Price: $ 3,399.95

DLP technology is a state-of-art display solution that utilises optical semiconductor to digitally manipulate light. The design is highly reliable and the all-digital circuitry delivers the best resolution in picture display across the broad range of products available, including the large screen TVs and projectors, used for home, offices, professional venues and digital cameras. The technology is highly dependable and manufactured by renowned display electronics companies, where more than ten million systems have been shipped to more than 75 end-product manufacturers since 1996.

DLP technology is in use wherever excellence in visual display is in demand. As versatile as it is, it is the only technology in the world that supports the world's smallest projectors less than 2lbs in weight, to the largest movie screens up to 75 feel. The result is a picture of immaculate clarity, with brilliance and colour, un-matching to any other display equipment in the world, having maximum fidelity.

The new technology started to evolve during 1970's, when Larry Hornbeck, of Texas Instruments (TI), came out with a new development of the first version of the DLP technology. This technology became available in 1996 for commercial use. The technology utilises small micro-miniature mirrors to create the image. These mirrors are laid out in a matrix on a semiconductor chip. These semiconductor devices are called Digital Micro-mirror Device (DMD), where each mirror represents one pixel in the image projected. The resolution of the image depends on the number of mirrors utilised and are specified as, 800x600, 1024x768, 1280x720, and 1920x1080 (HDTV) matrices, which are some of the common DMD sizes. These mirrors can be positioned very rapidly to reflect light, either through lenses or on to a heat sink, called light dump in Barco technology. The DMD varies the intensity of the light reflected, when rapidly repositioned, which is essentially a logical switching off and of the mirror position. The intensity of light reflected out of the lens, creates shades of gray, white when the mirror is in "on" condition, and black when its in "off" condition.

The technology works with a rear projection unit, and these create the picture by manipulating light, where the light comes from a centralised source and is projected on the screen. DLP principle works by deflecting light, in which, the complex system of mirrors reflect or deflect red, green, and/or blue light through an optical projection lens. This goes on to the front screen to provide you with a high resolution picture quality. The mirrors switch on when the light is required to be reflected and switches off when it is necessary to deflect. With high speed switch on and off, the system provides gray scale at a staggering accuracy. The distance between each DMD is less than one micron and with this distance, which is not seen by the naked eye, the complete group of DMDs looks like a solid sized mirror, which contains millions of micro miniature mirrors arranged in a grid pattern. The individual DMDs are independent of the other on that grid that they are assembled on, and are capable of reflecting light in two directions, either 10 degrees away or 10 degrees towards the optical lens. The reflections on the optical lens are projected on to a screen at a definite pixel. When the light is deflected away from the lens, it is absorbed by a light absorber and with no light reaching the screen a dark square image is formed on the screen at that particular pixel.

In this way the visual artifact that is seen, is best described as rapid and brief flashes of red, blue, and green "shadows." This is most often observed when the projected content features bright/white objects on a mostly dark/black background. DLP has a contrast ratio of about 2500:1, which captures the blacker of the blacks, crisper whites, with images that burst into life. The DMDs are fixed on a hinge and with millions of mirrors mounted on each one of them, it produces a precise, razor-sharp picture, with the mirrors switching on and off at the rate over 15,000 times per second.

The DLP technology incorporates a colour wheel, that travels to the surface of the DMD panel, as a light source, generating white light in a DLP projection system, passes through the wheel. The light is then filtered by the colour wheel into red, green, and blue, from which a single chip DMD can create at least 16.7 million colours. The 3-chip DMD is capable of producing a minimum of 37 million colour shades. The on and off feature of each of the mirrors are co-coordinated with the three major colour range. In this way, the mirror, meant to project a purple colour, would only reflect red and blue light to the projection surface. The alternating flashes make us see the intended hue on the screen.

The design of DLP is such that the data in the form of binary digits of light specific information or the image code is held in a series of Static Random Access Memory (RAM) cells situated within. The desired movement on the micro-mirrors is established by the content of this data when made available to the DMD modules from the RAM, where a digit "1" would signify a +10 degree tilt and a "0" would tilt the mirror at an angle of -10 degrees. This is the "on" and "off" mode of switching that was discussed previously.

The DLP TV technology reproduces colour which has a range up to eight times greater than that of an analog TV projection system. DLP technology is known to produce the darkest of black and crisp darker shades than that of other technologies used in TV. With the Sequential Colour Recapture (SCR) being introduced, the DLP technology will bring in up to 40% more lumens to the screen than was previously possible.

Since the time of its commercial introduction, the technology is fast growing in demand for its economical application, with no less capability, in various large screen TVs. The DLP technology is now the heart of many PAL DLP TVs, manufactured by well known organisations like, RCA, Samsung, LG, Toshiba, Zenith, and Panasonic, to name a few. It is expected that, with so many of these renowned companies taking up DLP technology, DLP TV will soon have quite a substantial market share in the modern TV market.

The technology makes video projectors, home theater systems, and televisions more robust and more reliable. The DLP technology has increased the mean time before failure rate to a very high level, being not susceptible to heat, humidity, or vibration, unlike other technologies used in TVs, which are environmentally more prone to failures with image degradation over time. The projection system of a DLP TV has an immaculate original picture presentation time after time, with minimal maintenance. For example, DLP TVS require no alignment as the analog TVs, and are not subject to burn-in and uses half the energy compared to most other TVs.

About the Author:

John Dulaney is an international traveler and an expert in overseas audio video equipment and cell phone communications when traveling abroad. His website Planetomni, carries thousands of multisystem TVs, VCRs, region free DVD players at deeply discounted prices. Planetomni also offers a large selection of prepaid cell phones, cell phone rental and satellite phones for rent or purchase.

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