Projector : What is it?
Projectors display images, movies, and videos onto large screens using lights and lens systems. They usually obtain images from slides, transparencies, or storage media such as hard disks and flash drives. They are commonly used in classrooms, conference rooms, and home theater systems. They are designed to be used in ark or dim rooms to enhance color increase contrast. Most modern projectors can also correct flaws in the original image, such as color, curves, and blotches.
Kinds of Projectors include the following:
- Overhead projectors are designed to display slides and transparencies.
- They consist of a large box with a light bulb, a mirror, and a glass top. The transparency is placed over the top and projected onto a screen or flat surface.
- They produce a lot of heat and usually come with fans to prevent burning and overheating.
Cathode-ray tube (CRT) projectors
- CRT projectors use phosphor-coated tubes to produce light and project the image. Most models have a red, green, and blue tube.
- They have better contrast and produce deeper blacks than other models.
- They require lower maintenance than newer technologies, which use delicate lamps and tend to overheat.
Liquid crystal display (LCD) projectors
- LCD projectors have light panels divided into small squares, each representing one pixel. They usually have three panels for projecting red, green, and blue light.
- They use halogen lamps to produce high-intensity light and achieve the right color temperature for the image.
- They allow a wider range of colors, but are usually less sharp and accurate than CRT projectors.
Digital light processing (DLP) projectors
- DLP projectors have microscopic mirrors arranged on a semiconductor chip. Each mirror represents one pixel.They control brightness and intensity by adjusting the angle of the mirrors.
- The mirrors can also be completely blocked, resulting in perfect blacks and much deeper colors.
Liquid crystal on silicon (LCOS) projectors
- LCOS projectors are similar to DLP projectors, but they use liquid crystals instead of mirrors.
- Their maximum image size depends on the amount of light produced by the lamp.
- They are ideal for projecting feeds from flat panels and large, high-definition TV screens.
|Resolution: Choose a projector with a high resolution if you want to display large, high-quality images. For small classrooms and conference rooms, the ideal resolution is SVGA (800 x 600 pixels) or XGA (1024 x 768). For large venues like stages and auditoriums, look for a model with a 720p (1280 x 720) resolution.|
Brightness: Make sure the lamp brightness is proportional to the size of the display screen. A rating of 1000 to 1500 ANSI lumens is ideal for small screens, while 1500 to 3000 lumens will work for medium-sized ones. For large screens or rooms with open lighting, choose an ANSI rating of over 3000 lumens.