Rear Projection – DLP Televisions
Although Plasma and LCD flat panel televisions seem to be all the rage these days, with growing numbers of consumers reaching into their pockets to buy the stylish sets, they are still out of reach of most average household budgets.As a result, the rear-projection TV (also referred to as an RPTV), with its lower pricing yet high performance, is taking center stage in the consumer television market.
Definition Of Rear Projection Televisions
The actual term “rear-projection” comes from the fact that the image is projected and reflected onto the screen from behind the screen, unlike traditional video and film projection in which the projector itself is placed in front of the screen, such as in a movie theater.
The Elements Of Rear Projection Television There are five basic elements in the construction of a rear-projection television. First, there is the type of projector technology used to produce a video image. Second, the type of lens assembly used to magnify the projected image. Third, the necessity to employ a mirror to reflect the projected image. Fourth, the screen upon which the reflected image is presented. Fifth, the sealed box that contains all of the previous elements
DLP (Digital Light Processing) is a technology widely used for projecting images from a monitor onto a large screen for presentation purposes. A DMD (Digital Micromirror Device) is used to create sharp images which can be clearly noticed even in a normally lit room. Developed in the 1980s by Texas Instruments (TI), DLP became commercially available in the late 1990s. Texas Instruments remain the sole manufacturer of DLP technology.
How DLP Works
Before the development of DLP, most computer projection systems were based on LCD technology which tends to generate blurry and faded images. DLP utilizes tiny mirrors housed on a unique kind of microchip known as a DMD (Digital Micromirror Device).
A DMD is a memory chip covered with hinged, microscopic electromechanical mirrors, one for each pixel on the screen. The number of mirrors used in a DMD is equivalent to the resolution of the displayed image. 800×600, 1024×768, 1280×720, and 1920×1080 (HDTV) are some of the most common DMD sizes. The mirrors in a DMD can be quickly repositioned to reflect light through the lens or onto a heatsink. This is termed as a light dump.
