How The Cheapest Type Of Projection TV Works.
The cheapest projection TV available on the market today is a DLP Projection TV. This type of technology is widely used for the data projectors that have all but replaced the old overhead projectors (this is an example of front projection). And DLP projection TV is also used as rear projectors - usually as rear projection TVs. As DLP projection TVs are the cheapest projection TVs, it is not surprising that they have sold over two million units and have a 10% of the flat screen TV market share.
So what do you need to know about DLP projection TVs, apart from the fact that they are the cheapest type of projection TV? First of all, you need to know what DLP stands for (it makes them easier to remember, for one thing). These initials stand for Digital Light Processing, and it was first developed in the late 1980s. DLP technology makes use of another set of three initials: DMD. DMD is a key component of this cheapest type of projection TV. While it is a vibrant new technology, it actually makes use of one of the oldest pieces of audiovisual technologies: mirrors. DMD stands for "digital micromirror device", which gives an impression of how this technology works. A DMD consists of a matrix or array of tiny mirrors, each of which represents one pixel in the screen. It is wise to bear this in mind if you are looking for the cheapest projection TV - you get what you pay for, so if you choose a model that has a smaller number of pixels, it may be cheaper but the picture quality will not be as sharp. Each of the tiny mirrors inside a DMD can be shifted incredibly rapidly so that the mirror itself either reflects light through the projector lens or into what is known as either a "heat sink" or a "light dump". This either-or situation means that the DMD is a digital rather than analogue device. The light reaching the screen of the projection TV is given colour by one of two devices. In the cheapest type of projection TV using DMD technology (single-chip projectors), a colour wheel spins. If you remember back to high school science, you should remember that there are three primary colours of light: red, green and blue. As single chip DMDs actually project three images - a red one, a green one and a blue one - in very rapid succession, a flickering known as the rainbow effect occurs, which can trigger migraines, headaches. So while a single chip DMD is the cheapest type of projection TV, you will probably end up spend the difference between the basic and the better models in painkillers. More sophisticated versions of DMD have a three-chip system where each chip (each with its own array of micromirrors) receives a different spectrum of light, which has been split from the original white light of the lamp. This technology, while it is not the cheapest type of projection TV, greatly reduces flicker and the "rainbow effect" and can allow the screen to display as many colours as the human eye can detect, if not more. |