History
In 1922 the first public 3D film ‘The Power of Love’ was released in a movie theater using red and green anaglyphic 3D glasses.
Anaglyph glasses were the first type of 3D glasses, invented by Edwin H. Land, who patented them in 1952. These used stereoscopy to create two different coloured lenses, red and blue, to create the illusion of 3D depth.
Today, 3D glasses fall into two main categories, passive or active. Passive can be further sub-categorised into anaglyph or polarized 3D glasses, and are used in movie theaters. Active glasses are only used for home cinema systems.
Passive 3D Glasses:
Anaglyph glasses – Use two different coloured lenses.
Polarized glasses – Use two different polarizing lenses.
Anaglyph
Anaglyph glasses use two different coloured filters to view two different coloured images on the screen, that are slightly offset from each other. When our eyes view each of these images through the glasses, it creates the illusion of depth for our brains as each eye is looking at something different. For red/blue glasses, the blue lens only lets the red image through, while the red lens only lets the blue image through.
In reality, there are many two combinations of colours that can be used, however, to achieve the best stereoscopic vision possible, the colours should be diametrically opposed (completely opposite). Initially, the colour of these lenses was red and the other in either green or blue. Later they were adjusted to red/cyan, as the cyan allowed for better contrast and colour perception. These glasses were made from cardboard, and were used for both movies and comic books. Today, anaglyphic glasses are still used in the academic and scientific worlds.
![](https://3dmoviereviews.com/wp-content/uploads/2023/01/Kids-with-Anaglyph-3D-Glasses.jpg)
Polarized
Polarized 3D glasses use orthogonal polarizing lenses, where one lens is vertically polarized, while the other is horizontally polarized. This technology was introduced in the mid-1980s. Unlike anaglyph glasses, these have a yellowish-brown tint and were made more stylish by using durable plastic instead of cardboard (though cardboard ones were used too).
Polarized 3D glasses, like sunglasses, work by only allowing certain wavelengths of light through, then merging the two images together using two different polarized lenses, which creates a more impressive 3D image.
This requires the images to be polarized as well. The vertically polarized lens will allow the horizontally polarized image through, and the horizontally polarized lens will allow the vertically polarized image through.
![](https://3dmoviereviews.com/wp-content/uploads/2023/01/RealD-Cinema-Glasses-1024x666.jpg)
Active 3D Glasses:
Shutter glasses – Use battery-powered shutters.
Shutter
Active shutter glasses use battery-operated lenses to control the light entering each eye. These glasses receive a signal from the playback device so they can synchronize and rapidly open and close each of the shutters in time with the movie. When the left lens is open, the right is closed, and vice versa.
They flip back and forth faster than our brain can perceive creating the 3D effect, refreshing up to 144 times a second (144 Hz).
When first introduced, active shutter glasses used infrared emitters to sync with the movie, but a synchronization system was created called DLP-Link, which today is built into modern 3D-ready DLP projectors. DLP-Link creates a uniform system that allows any DLP-Link glasses to work with modern projectors.
![](https://3dmoviereviews.com/wp-content/uploads/2023/02/Samsung-3D-Shutter-Glasses-1024x683.jpg)
Virtual Reality:
Over recent years, we have also seen a rise in Virtual Reality (VR) based devices used for viewing 3D films, such as the Oculus VR devices, HTC Vive, or HP Reverb G2. These devices often allow for 360-degree movies on top of the 3D experience, meaning you can dodge and weave objects flying at you. The downside of VR devices is that they are still relatively expensive as they can only be used by one person at a time.
The Future
It can be argued that the 3D film industry is being held back by the need for glasses. Some people do not like the third dimension at all and complain of headaches when watching a movie.
There have been quite a few demonstrations of glasses-free TVs in the past. However the technology is still way too early and requires the viewer to sit at a very precise position in order to experience it. This also restricts the number of viewers.
I believe shutter glasses and VR technology will be here to stay for quite a while and the technology will continue to improve, whilst becoming more affordable.