What Is A Projector?

Date First Published: 11th July 2023

Topic: Computer Systems

Subtopic: Computer Hardware

Article Type: Computer Terms & Definitions

Difficulty: Easy

Difficulty Level: 2/10

CONTENTS

How Do Projectors Work?
Types Of Projectors
Front vs Rear Projection

Learn about what a projector is in this article.

A projector is an output device that projects visual images and text from a computer onto a wall, screen, or another large surface. It is useful when watching TV and films, and in classrooms to display presentations so that everyone in the room can see them. Most projectors use either a VGA or HDMI cable from a computer to send the images to the projector.

Projectors are capable of reproducing images and text onto large, flat, and lightly coloured surfaces, such as a white or light-coloured wall or whiteboard. Projectors come in lots of different shapes and sizes and standard projectors are only a few inches tall and around a foot long and wide. Some may be portable and others may be fixed to ceilings.

How Do Projectors Work?

Most projectors work by shining a light through small transparent lens to create an enlarged image on a screen, allowing the view of a small document or image to be shared with a large audience, but some newer projectors can directly project the image using lasers. For example, a retinal projector is one that directly projects an image onto the retina rather than using an external projection screen.

Types Of Projectors

Projectors are categorised based on the technologies they use to reproduce images. Some types of projectors are:

4K projectors - A projector that has 4x the number of pixels of 1080p projectors, allowing for a smoother display, higher frame rates, and more saturated colours.
LED projectors - Uses LEDs as its light source to project images onto a screen.
Laser projectors - Projects charging laser beams on a screen to create an image on a screen.
Overhead projectors - Creates images using a flat, transparent sheet and displays them on a screen using an overhead mirror.
Movie projectors - An optomechanical device used to display motion pictures by projecting them onto a screen.
Video projectors - Receives video signals and projects them onto a screen using a lens system.
Handheld projectors - Also known as a pocket projector, mobile projector, or pico projector, a handheld projector is a small, portable projector that runs on batteries and can be integrated into mobile devices.
LCD projectors - These work by sending a high-intensity coloured light beam through an LCD panel. They are very popular because they are lighter and can provide crisp protection.
DLP projectors. These use tiny mirrors for each pixel of the image to project high-quality images.

Front vs Rear Projection

Projectors can be used for displaying images on the front or rear. In front projection, the screen is opaque white and in rear projection, the screen is semi-transparent grey. Front projection sends the images to the front of the screen from the position of the audience. This type of projection is more common than rear projection since it does not require an empty space behind the screen. Classrooms and offices often use front projection.

Rear projection sends the images from behind the screen towards the audience. Compared to front projection, it is less affected by ambient light and provides better contrast. It is often used in outdoor settings and commercial areas where more space is available.