Technology Explained

3D TVs: What They Are, How They Work, & What Can They Show In 3D? [MakeUseOf Explains]

James Bruce 24-10-2012

what is 3d tv how it worksIf you’re in the market for a new TV, chances are it’s going to be 3D – not because you particularly want one that can do 3D, but simply becuase 3DTVs typically have better displays than their plain HDTV equivalent. Today I’d like to explain about the different types of 3DTV as well as touch on some confusion that surrounds them.


Types Of 3D Display

To misquote someone famous who may have never existed – all 3D displays are not created equally. In fact, there are three basic 3D display types available, whether you’re dealing with TVs, monitors, or gaming handhelds.

Active Shutter

Active shutter 3D displays work by displaying frames sequentially; one frame for the left, then one frame for the right eye, then repeat. Using powered glasses with LCD screens in them that are synced to the same frequency as the TV, the glasses alternative between blocking the vision of each eye. The left eye is shown the frame for the left portion of the scene; then it blacks out, and the right sees the frame for the right portion of the scene.

This sounds annoying, but in reality it happens so quickly – around 60 times a second – that you barely notice. I say “barely”, because some people do notice a slight flashing, and often report headaches after prolonged usage.

what is 3d tv how it worksYou can tell which TVs are “active shutter” because the glasses will require recharging via a USB cable, or have small user-replaceable batteries. They also weigh more, and cost more than other types of glasses – so an additional pair may set you back about $50 or more.

However, active displays are generally considered to be the best quality of 3D due to the fact that each frame is completely blocked from the other eye, leading to less “bleeding” between images (where you can see both frames at the same time in some situations). You’re also getting a higher brightness due to one frame being sent at any one time; passive displays show both the left and right images at all times.


Passive (Polarised)

Passive 3D displays work by displaying both the left and right frames simultaneously. Each frame is run through a different polarising filter – this “aligns” the light waves into one direction only. When those light waves hit your 3D glasses, they come against another set of polarising filters, such that only light destined for the correct eye is allowed to pass through.

what is 3d tv like

The quality of passive 3D is not quite as good; it’s a primitive technique, and simply doesn’t allow for as much depth as active 3D, as well as suffering from generally murky images. Since you’re blocking half of the total brightness given out by TV, you also end up with a darker picture than you would with an active display.

what is 3d tv like


On the plus side, the glasses used for passive TVs are very cheap; it’s likely your TV will actually come with 8 pairs. They also don’t need batteries, operating purely on the power of physics! Cheap and cheerful – great if you have kids and expect glasses to break often or gets KFC grease on them constantly.

Lenticular (Glasses Free)

Lenticular is the technology behind the new breed of 3DTV that doesn’t need glasses, and some existing consumer devices like the viewscreen on 3D cameras and the Nintendo 3DS gaming console. The technology is a little like the optical illusion “hologram” cards you used to get in cereal boxes; as you moved the card around, a different image would be displayed.

what is 3d tv like

With lenticular 3DTVs, light is directed at specific angles such that if you closed one eye and walked around the TV, you would see alternative left and right frames. It’s an interesting technique, but in reality it means there are only a set number of places from which you can view the TV (and don’t even think about doing sillly things like lying down to watch a movie or twisting your head slightly).


what is 3d tv how it works

With 3DTVs rumored to be launching in early 2013, you should be aware of the issues I’ve mentioned about specific fixed viewing angles. Although many people believe that “glasses free” is the future of 3D, the fact is the quality of 3D displayed on these devices currently is very poor, something that Twentieth Century Fox has also warned about.

2D To 3D Conversion / Emulation

Most 3DTV’s come with a 2D to 3D conversion mode that magically turns a regular 2D broadcast into a 3D one. Avoid these like the plague. Using a series of algorithms, the TV attempts to analyse the picture and distinguish the foreground objects from the background. Then to create the 3D illusion, foreground objects are pushed apart, creating the sense of “closeness”.

Humans are suprsingly good at this; if you close one eye, you still have a fairly good idea of the depth on each object you’re seeing, because you’re able to combine knowledge of what the object is, how big it should be, perhaps how far away it was in the past, etc. Trying to ask a computer to analyse the scene in real time and figure out where each object is – now that’s just difficult. I showed you a similar technique in Photoshop Old-Time Fun: How To Make 3D Images For Viewing With No Glasses Believe it or not, you don’t actually need 3D glasses to experience convincingly realistic 3D images (or movies). You just need to make yourself go “crosseyed”. Essentially, you look at two images, and by intentionally... Read More a few months ago, with less than impressive results.


The trouble is that no matter how much analysing you do, the results will always be poor. It’s like trying to reconstruct the sounds of a live orchestral piece from a badly encoded 64kbs mp3 recording of one. It simply can’t be done. So my advice is not to enable 3D mode for everything; just for things that are actually broadcast or recorded in 3D.

So What Can You Play On a 3DTV?

Over The Air & 3D Cable Channels: The BBC has been fairly prolific with 3D broadcasting this year for both Wimbledon Tennis and the Olympics; while Sky has a 3D channel available (you may need to sell a kidney or two to afford the monthly charges though).

3D Blu-ray: Get a 3D comptible Blu-Ray player, or just buy a Playstation.

Playstation 3: Supporting both 3D Blu-Rays and an extensive collection of games, Sony is really leading the way with 3D offerings.

Xbox 360: A very limited selection of games support 3D mode; including Call of Duty Black Op2, launching this November.

PC Games: Grab some third party drivers from and have the world of 3D gaming open up to you. Note; these don’t magically turn your PC in a graphical power machine – if your computer can’t handle regular gaming, then it certainly can’t handle 3D gaming. In fact, you’ll twice as much power since you’re effectively driving 2 displays.

I think that explains the technology behind 3D TV’s and what to watch out for when buying one. I hope you can make an informed decision, and understand a little more about how they work and what content is available. Comments and suggestions welcome – however, please don’t ask “can my laptop / non 3D-TV play 3D movies?” – because it can’t.

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  1. Overlod Eyser
    October 27, 2012 at 1:01 am

    Nice info

  2. Larry
    October 26, 2012 at 3:38 pm

    Definitely good info...just one do these various technologies look when attempting to watch non-3D you just not use the glasses and see a great image...or do you see some quality issues?

    • Muo TechGuy
      October 26, 2012 at 4:02 pm

      Non-3D content is just ... normal.

  3. Kofi Agyeman
    October 26, 2012 at 8:13 am

    i have a 3d tv but never used the 3d function

  4. zbuckone
    October 25, 2012 at 10:40 pm

    This is an excellent article giving you an overview of the currently available technologies used in the 3D capable TV's. The article is up to date and excellently written.

  5. Vishal Mishra
    October 25, 2012 at 3:30 pm

    Beautifully explained. thank you.

  6. Ksavai
    October 25, 2012 at 12:44 pm

    Very useful article. Thanks.

  7. Richard
    October 25, 2012 at 8:27 am

    I have 2 3D LG TVs (2011 passive 3D 55" & 42" LED models).

    All my 3D materials comes from avi/mkv files. I do not have any other 3D players.

    Surprisingly, the 2D-3D conversion does a pretty good job! We even tried it on the XBox 36 games - it does a credible enough job to give even a fast paced game like Transformers a decent 3D-like experience.

    However, I will not pay more than $50~100 premium for a $1000~2000 TV for the 3D features.

  8. Lisa Santika Onggrid
    October 25, 2012 at 4:55 am

    Your eyes will tire quicker watching these 3-D shows since you're actually see more than the normal 2D version.
    If I want 3D, I'm going to the cinema. They pushed 3DTV even in areas which don't have 3D shows published. Talk about marketing scheme.

  9. Rajeev Rohatgi
    October 25, 2012 at 4:01 am

    Thank you...was in the market for a TV, and had pretty much decided against 3D as so much snake oil. Might now require a rethink!

  10. Anonymous
    October 25, 2012 at 12:28 am

    This makes me aware of what kind of 3DTV to buy.. thank you.. great article James!

  11. Jim
    October 25, 2012 at 12:06 am

    LG vs Samsung 3D ?

  12. Igor Rizvi?
    October 24, 2012 at 8:42 pm

    I dont find this technology so "eye healthy" :S

  13. Anonymous
    October 24, 2012 at 8:13 pm

    well explained 3DTV tech

  14. Achraf Almouloudi
    October 24, 2012 at 8:04 pm

    You can turn off your Laptop integrated screen while playing using your 3D displat to avoid more using double processing power .

  15. Doug Grammer
    October 24, 2012 at 6:55 pm

    Great Info!

  16. Kashif Maqsood
    October 24, 2012 at 6:46 pm

    Great Article...very usefull info...really like your comment about the pricy 3D TV may indeed have to sell a kidney!!

  17. Anonymous
    October 24, 2012 at 6:09 pm

    cannot wait to have one of this kind of TV

  18. Florin Ardelian
    October 24, 2012 at 6:09 pm

    Wonderful article. Thanks for the heads up!

  19. Hanamichi Kurotsuchi
    October 24, 2012 at 5:54 pm

    thank you for this good article mr.James