Active v Passive 3D explained

• Active and Passive 3D refers to both the type of glasses you have to wear to watch 3D, and the 3D ready TV you are using.

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  Active glasses contain LCD lenses that alternately 'block out' each eye depending on whether the left or right image is being displayed on the screen. They are referred to as active because they require a battery to operate the LCD lenses. The shuttering occurs so rapidly that you don’t see the shutters just the 3D picture.

  

   

  Passive glasses do not require any power to operate them. They use polarisation to separate out the left and right image, then work with polarised TVs that deliver two images to the viewer. The TVs have a filter integrated into the screen, and when switched into 3D mode, the filter orientates the light emitting from the screen differently for the left and right image. Passive is the type of technology you may have seen in the cinema. The glasses are light and cheap to buy.

• How much does it cost?

  3D TVs are less expensive than you might think - these can be bought from your local retailer from as little as £700. You have to be a Sky World HD customer to experience Sky 3D, which is £62.50 a month, and the channel comes at no extra cost for Sky World HD customers.