Projectors & AV  
 
   
Home Contact Us Links
 
Home > 3D Projectors
 

 

 
  3D Projectors

 

The latest development in projectors is 3D technology.

It is not a new concept; it has been around for many years but the way it is now used in office or home digital projectors is only recent.

How does 3D work?

We see in 3D because each eye sees a slightly different image that our brain combines to show depth.

When using a projector the image projected is obviously flat so the "trick" is to project two overlapping images: one for the left eye and one for the right eye.
With the help of special glasses, each eye only sees one of the slightly different images and we then get an impression of depth.

Different types of 3D

There are a few different ways to show 3D using different devices. But as we are talking about projectors, we will stick to the methods used in current projectors.

  • Anaglyph 3D

When people think of 3D, many think of anaglyph 3D. This method has been available for a while and you may have even watched a anaglyph 3D movie on your TV already.
Basically anaglyph 3D uses two superimposed images with offset colours and you need glasses with two different coloured lenses (usually cyan and magenta) to see the image with some depth.

Anaglyph 3D glasses
Anaglyph image
   

Anaglyph 3D glasses

Anaglyph image

You don't need any special equipment to use anaglyph 3D, any display such as a TV, computer monitor or standard projector can show this type of 3D.

This technology is inexpensive; the glasses are usually provided for free with the DVD as they're cheap to produce.
However the result is often less than satisfactory for movie enthusiasts because the coloured lenses affect the brightness but also more importantly the colour of the image.

 

  • Active Shutter 3D

Active shutter 3D is the technology used in most of the current mainstream 3D digital projectors.
It requires special active shutter glasses that are made of glass containing liquid crystal and a polarising filter. The glass becomes dark when some voltage is applied.

The projector will show alternating 'left eye' then 'right eye' images at very high speed (up to 120 frames per second). At the same time the glasses will synchronise with the projector and alternately darken each lens, effectively blocking the view of one eye then the other.
This happens so fast that our eyes can't distinguish the alternating images and instead they are combined into one 3D image with depth.

Optoma 3D-RF glasses

Optoma 3D-RF shutter glasses

This technology works well because the glasses block the view of one eye at a time so ghosting (when one or both eyes see two different images at the same) is virtualy eliminated.
The downside is, because the glasses block half of the light, the perceived brightness will seem 50% lower so you should take this into consideration when choosing how bright your projector should be.

Also because the glasses are active glasses that require a special glass, a transmitter (DLP link, Bluetooth, Radio frequency...) and battery, they are relatively expensive to produce and to buy compared to alternative technologies.

 

  • Polarised 3D

Polarised 3D requires polarising filters on the projector(s). The filters make the light waves oscillate in the same direction while filters on the glasses only allow the light meant for each eye to pass through the lens. Each eye sees a different image creating a 3D effect.
Also required is a silver screen to maintain polarisation.

The glasses used in polarised 3D solutions are passive glasses and quite inexpensive making them ideal for large audiences.

Although there are a few polarised 3D projectors available to businesses / pubs / clubs, this technology is currently mainly used in high end solutions and cinemas / commercial applications because it requires one or two expensive projectors and accessories.

 

  • Interference Filter 3D

Interference filter technology 3D is another technology used in cinemas. Made by the German company Infitec, it is licensed by Dolby and is also known as Dolby 3D in cinemas.

Because it is only available in high end commercial cinema projectors, we will not go into further details here.

What is the use of 3D?

3D projectors are used in various applications.

They are very popular for home cinema as they allow film enthusiasts to enjoy 3D movies or 3D TV or even for gaming on a large screen.

They are very useful in classrooms where they help capture the attention of pupils and students.
There is 3D content available for education such as biology (human anatomy, frog dissection), science (explore the universe), geography, history (visit ancient monuments) etc.

They can also be a great tool for businesses, in particular for design work.