A Projector has become an inseparable part of offices, schools and universities. One can not imagine a presentation without the use of projector. Almost all presentation rooms has projectors installed. In this post we will discuss about what is Projector, how it works, its various types (CRT, LCD and DLP), applications, advantages and disadvantages.
What is a Projector
Before understanding the concept and working of a Projector, one should know what projection is. Projecting things or images onto a display screen is nothing new. All children enjoy Shadow play and though it is simple, yet it figures as the basis for projection technology.
Let’s understand how it works. Put an object or image in front of a light source and an obscure dim image of the object can be seen onto the wall or display screen. If you move object, it’s called an animated image.
Fig. 1 – Introduction to Projector
In simple language, a projector basically adopts the operational principal of image projection whereby the projector accepts a video/image input, processes it with the assistance of its inbuilt optical projection system consisting of a lens & optical source and projects the enhanced output on the Projection screen.
A projector is an optical device that projects a figure or picture onto a surface. This surface is usually light in color and it may be a projection screen, white screen or sometimes a wall. Projectors may be used as an alternative to a television or monitor in large gatherings.
For example: – A projector could be used to demonstrate a presentation on a big screen so that each one in the sitting area (may be a classroom or a conference room) can see it. Projectors can produce either still images like slides or moving images like videos. Often, projectors are about of toaster sized and weigh only a few kgs.
Types of a Projector
On the basis of its display property, Projectors can be classified in three types. They are:
- Cathode Ray Tube (CRT)
- Liquid Crystal Display (LCD)
- Digital Light Processing (DLP)
Fig. 2 – Types of Projectors
Cathode Ray Tube (CRT)
A CRT projector is basically a video projecting device. It uses a tiny cathode ray tube which has high-brightness for image generation. A Lens is kept in front of the CRT face which focuses the image and enlarge it onto a big projection screen.
A CRT projector focuses on the image or video by its lenses to project it on screen. These images are processed with help of three separate colored (red, green and blue) CRT tubes.
Fig. 3 – Cathode Ray Tube
CRT projectors are not portable as they are huge in size and heavy in weight. Their electricity consumption is also high because of three light guns. At initial stage, it may be difficult and tricky to set up a CRT projector, but the users say that a CRT projectors have a brilliant and outstanding picture quality. People say that these projectors are nevertheless than newer technologies and are compatible with new improvement.
Liquid Crystal Display (LCD)
The meaning of Liquid Crystal Display is approximately clear from its name. The word LCD resembles two states of matter, the liquid and the solid. A Liquid Crystal Display uses liquid crystal to project an image or object.
Fig. 4 – LCD Projector
These types of display panel is generally used in computer, Laptops, TVs, portable video games and cell phones. Displays in LCD technology are much thinner as compared to CRT technology.
Digital Light Processing (DLP)
Digital Light Processing (DLP) is a video innovation made by Texas Instruments that is utilized for front and back projection units. DLP is used in both back and front projections. It is regular for back projection in TVs and also utilized in front projectors for units intended for organizations and classrooms.
Fig. 5 – DLP Projector
A DLP comes in two noteworthy structures i.e. 1 chip DLP and 3 chip DLP. Digital Light Processing makes utilization of micro mirrors called a Digital Micro mirror Device to reflect light and shading onto a screen. These micro mirrors are situated in a semiconductor chip and are little. Most of the DLP chips are manufactured by Texas Instruments.
How a Projector Works
A projector is an optical gadget that projects a picture (or moving images) onto a surface, usually a projection screen. Most projectors create a photo through projecting a bright light via a small lens. However, some newer types of projectors can project the image directly, by using the usage of lasers.
Fig. 6 – How Projector Works
A digital retinal display, or retinal projector, is a projector that projects a photograph at once on the retina as a substitute of using an external projection screen.
Now, Pico Projectors are also in great demand as they are very small (handheld) in size and offers high quality image.
Applications of a Projector
The applications of Projectors include:
Projectors are used in schooling area for describing a topic. With the aid of a projector, videos or photograph become more enjoyable and children can easily learn by fun way. Further, we can easily zoom-in or zoom-out the image to clear the vision and to search minor points.
Projectors are used in big MNC’s and enterprises for meeting, presentation and conference purposes.
Projectors are even used as home theaters that permit you to see the movie or any serial on a massive display with a first-rate sound nice, which makes you feel like you are staring at live.
Fig. 7 – Applications of a Projector
Advantages of Projector
The advantages of Projectors include:
Large Picture Size
Front projectors generate the largest viable photo size. You can use them to create very large display screen experience of a business film theatre in your own home. Most projectors produce stunning pictures at sizes of 90″ to 120″ diagonal, which is far large than something you can get with flat screen TVs or rear-projection TVs.
Best Alternative for Large Screen Television
A projector is a cheaper substitute for a 60″ plasma TV. The projected picture is typically very bright and projectors can be used with some of the room lights on.
Fig. 8 – Advantages of Projector
Front projectors can be the least high-priced alternative for big display screen video in your home. Some projectors are constructed for devoted domestic theater and they have now dropped below $1,000, this price makes a good deal; less steeply priced than flat screen TVs or rear-projection TVs.
Given the low price of many entry-level projectors, this is the least expensive way to get a big screen experience at your home. Though you may have to attach an additional speaker, yet the experience you get is much better compared to price.
A small projector that is set on a rear shelf or bookcase or on the ceiling takes up no floor space in the room. When not in operating mode, it is hardly visible.
Easy To Install
They are lightweight, and one person can pull it out of the box, hook it up and get an image on the wall with little trouble.
Disadvantages of a Projector
The disadvantages of Projectors include:
- A dark room is very often required to use a projector.
- It requires maintenance on regular intervals.
- Installation Cost can be more in some cases as it depends upon how you get it installed.
- Most of the projectors need a separate audio system.