LCD projectors

LCD projectors are used to enlarge the image in a transparency or other digital source and project it on a wall after magnification. Motion picture projectors are slightly different because in them the transparencies are arranged in a long reel. Each frame in the reel is in front of the projector lamp for a brief period of time. A continuous stream of frames in way creates a moving image on the screen by using the persistence of vision in the human eye. A different apparatus reads the audio that accompanies a movie.

High Definition (HD)

LCD projectors are constructed with a special emphasis on projecting high-definition video that has a much higher pixel density (resolution) than older projectors. LCD projectors also have the advantage in terms of weight and smaller dimensions. Most newer models of LCD projectors use 2-inch poly-silicon panels that are good in projecting high-resolution. Some projectors even use TFT panels that can almost match the High Definition requirement of over 1000 scan-lines. 
Keeping further in touch with modern display requirements, some manufacturers are now making LCD projectors that can work with the 16:9 aspect ratio rather than the traditional 4:3. These are the projectors that deployed in sports bar and similar places where the audience prefers a wide-screen format.

The TFT advantage

TFT LCD projectors use 3 high-definition 2-inch poly-silicon TFT panels. Each panel represents one of Red, Green, and Blue (RGB) colors to create the whole spectrum. LCD projectors can create an image contrast of nearly 400:1 depending on the model. Most competent LCD projectors will also increase the brightness levels of all media by more than 40% as compared to traditional projectors.  
In several ways the LCD projector is a high-tech evolution of the slide and overhead projector. LCD projectors employ a small and colored LCD panel that is place in front of the projector lamp. The actual images are taken as input from several electronic devices like DVD, VCR, or even a computer. Since LCD projectors are a lot smaller and lighter than other types of projectors, they are also very convenient to move around. Another reason for the popularity of LCD projectors is that they do not require any additional furniture like an oversized television would. The lens in the LCD projector is capable of casting an image on to any flat surface.

Resolution and cost

There is a simple rule that applies when buying LCD projectors. The greater the supported resolution the higher the cost will be. For most purposes a regular resolution will do, for example a resolution of 400 is sufficient for watching DVD. The need for higher resolution comes in when the minor details become important. A LCD projector with a 400 resolution will not be the right choice for viewing HD-DVD. The light-output of the projector is calculated and represented in ANSI lumens. The lumens requirement depends on the size and ambience of the room. Classrooms can do with 1000-2000 lumens while huge conference halls require between 2000-3000 lumens. Another factor that affects projector quality is the contrast ratio. This ratio is defined as the ration between the brightest and the darkest spots in a given image. The best projectors are those that can project a contrast ratio of at least 400:1 or higher.

Portability

In many cases the projector would require frequent shifting to different rooms or even wider locations. Most LCD projectors weight lower than 5 pounds and make an excellent choice for people seeking portable projectors. Portable projectors are also required to plug in to various kinds of device so they must be equipped with the all the common forms of inputs they might be expected to receive and process.

  The last but equally important factor is the peak lamp life of the projector lamp.