How Modern LCD Projectors Work

Types of projectors

Before we jump into how modern LCD projectors work, lets look into the types of projectors. There are three types of projectors, LCD, DLP and LASER projector

LCD projectors
History of LCD projectors

The first projector was subtly engineered in the year 1984.  It was an LCD projector. Its inventor was Gene Dolgoff after experimenting with the idea since 1968. Today, despite the countless and unceasing advancement in display technology, projects still remain relevant. The first projectors worked efficaciously in a simple way.

LCD projectors proved to use less power than the CRT and more so reliable and lighter. Additionally, they have been smaller and cheaper. On its own, LCD project is useless and it requires a wall or a screen from where all the images are project. White sheet will suffice.

Method of projection

There basically only two types of projection; front end and back end projection. The traditional projectors -LCD, LASER and DLP- work using front end projection. This basically means that the screen is placed in front of the audience. You could be wondering how back end projection works. Well, the audiences are behind the screen. This is how the current television sets and other modern display screens work.

How modern LCD projectors work

This is how the modern LCD projectors work; the process begins with the production of a very bright light. There many light sources used. The commonly used light source are lasers, LED and xenon arc lamps. These beam is directed to a group of mirrors. It is a bit different from how Digital light processing projectors work.

how modern LCD projectors work
How a colored imaged is produced by 3LCD screens

There are two special dichroic mirrors (they have a special coating). Dichroic mirrors special attributes make them reflect only one type of wavelength. Once the light hits the mirrors, it is split into three primary color light, blue, green and red.

Read more on OLED display Technology and what OLED mean

The light is made to pass through the LCD screens.  There are three such screens in a projector. LCD screens has special attribute than makes it either allow light to pass through or block when electrons pass through it. An LCD screen contains numerous tiny pixels. Now when the light passes through the three LCD screen is tilted red, blue and green. However, each screen can only tilt it only one color only.  To produce a colored image, the image is finally passed through a dichroic crystal which gives birth a countless colors.

Pros and Cons of an LCD

You will realize that there are both advantages and disadvantages that are associate with the LCD. Despite their unceasing persistence in the market, LCD has numerous disadvantages that has led engineers to seek ways to improve them; and sometimes seek better alternatives. However, let us first look at their advantages first.  What can the 3 LCD projectors do that other types of display cannot do? Well, for starters, the image is very clear and detailed using only 25% less electricity that other projector technology.

Secondly, you do not have to worry about wearing out of the film or the data storage since they rely on the external source of data.  For instance, most projectors rely on either a camera, DVD or a computer.

Thirdly, LCD projectors do not have the rainbow effect that the DPL projectors experience. DPL projectors have a color wheel that spins. Additionally, LCD projectors enjoy the high contrast ratio that makes them have images that are sharper. Finally, they very cheap compared to the LCD. For instance, while the DPL projectors could be going for more than $ 34,000 while LCD projectors cost less than $ 10,000.


The disadvantages of LCD projectors is that they require maintenance and upkeep. It is common knowledge that pixels burn out and with time the quality of image reduces. Further, dust is known to settle on the LCD screens making the image appear smudged.

Currently, many projectors require a separate audio system such as Bluetooth speakers etc. it means that if you need to listen to sound, a separate system will have to be carried out.  This makes using them a very tedious endeavor. Most these devices require a dark room for the images to be clear. Today, there are special projectors that can be used even when the lights are on in a room.  Take a look at the best outdoor projectors for daylight.

projector LUMEN

Lumen is the unit used to measure brightness of any source of light. The higher the lumen the brighter the source of light, in this case the projector. ANSI lumen is the industrial term for the lumen.

The average amount of light from a lamp projector is 2000 lumen but a laser project emits at least 3500 lumen.

For comparison purposes, here are some of the common light source you know about and the amount of lumen they emit

Light source Amount of lumen
Candle 14 lux
Sunny day 100,000 lumen
Fluorescent 400 lumen
100 W bulb 1600 lumen


Benefits of a projector

Here the benefits that projectors have over other types of displays.

Portability: projectors of whichever kind are highly portable today because of their light mass and small sizes.  This is not the case with the current 56” screens whose likelihood of being broken outweighs its need for mobility. Furthermore, projectors come with their special bags from which you can carry them around. Their lightness makes sure you can carry them for a prolong periods of time or for long distances without exhaustion.

Enlarged images: the images from projectors can be very large depending on the distance between the screen and the projector. Additionally, such images would be sharper, detailed and very clear due to the high resolution and contrast ratio of the projector. Unlike a 24” screen a single projector can be used in a room full of 100 or so people.

Adjustable image size: Unlike all other types of display, projectors posses an attribute where you can adjust the sizes of the images as much as you would like. Such attributes include the use of keystone correction and the lens zoom.

Eye comfort: Finally, eye comfort is one of the major factors you have to consider when going for any type of display. The eye comfort is a function of the amount of light from a screen. Unlike many LED, LCD and OLED screens, the projectors brightness can be adjusted as much as you wish. Furthermore, the type of screen used for the projector can always be changed accordingly. The above-mentioned types of screens have blue light from pixels emitted with higher intensity than other primary colors. This is the primary cause of strains you experience when watching a movie.


Projectors have unceasingly evolved over the time. Their uses and benefits are undeniably many so even are their varieties and type. Today, you will find that the most common uses of projectors are power point presentation at workplace or as a display screen for other devices such as computers and DVD.  You have unlimited options to choose from depending on their uses and your budget. However, there are a number of factors you need to consider before going for a projector.  Such factors include lenses, base stage, lamp life cycle among others.

DLP projector (Digital light processor)
Laser projector