Technology duel: Shutter glasses versus polarizing glasses

The most common in the PC area is the shutter glasses. The corresponding monitors operate instead of the usual 60 hertz (Hz) with a frequency of 120 Hz, in order to alternate images for the left and right eye. The shutter glasses darkens the respective eye synchronously, so that it only sees the corresponding image. Although darkening is very fast, some users perceive a slight flicker.


3D with Shutterbrille


The effect is enhanced when the room is lit with fluorescent tubes or energy-saving lamps. The darkening of the glasses also leads to a clear loss of brightness. In order to display the fast image changes, a 3D monitor must also have a very short reaction time. The screen and glasses must be synchronized so that darkening is exactly the same as the images on the monitor.


3D with Polarization


In the case of cordless spectacles, this is done via infrared or Bluetooth, a corresponding receiver must be placed next to the screen or installed in the 3D monitor. Kabellose eyeglasses therefore have a built-in rechargeable battery, which must be recharged via a USB cable.


GeForce cards: Nvidia 3D Vision


Even in 2D mode, 120 Hz monitors have advantages. The simple moving of Windows windows on the desktop is much smoother: The light jerks normal with TFT screens and the blurring of the font is significantly reduced at 120 Hz.


In contrast to the shutter technology, the two images for the right and the left eye are combined into a single FullHD image. The trick is that the image lines alternately contain information for the left and right eye. A filter mounted on the display provides the polarization of the light. A corresponding polarizing lens ensures that each eye can only see its image.


Polarizing spectacles should be familiar to most users of the cinema: they are light and comfortable to wear. Since they do not have to be synchronized with the screen, no communication is necessary. Polarizing spectacles do not need any power supply, the problem of the flicker is also eliminated. Since the image is not darkened, the polarizing lens lets more light through: The 3D image is lighter.


A disadvantage of this method is a loss of the resolution since no two frames are displayed but only half the resolution. Polarizing monitors run with the standard refresh rate of 60 Hz, the more fluid 2D representation of the 120 Hz monitors is eliminated. After all, when viewing 3D movies, the disadvantage of the lower resolution is not so noticeable. If fonts and menus are displayed, however, you can see the missing pixels.


The first PC monitor with polarizing filter is the LG D2342P (23 inch, price: 299 Euro). AOC will be followed by another 3-D polarity filter TFT from July with the e2352Phz (23 inch, price: 249 Euro).


The best selling PC-Shutter-glasses is the 3D Vision of Nvidia, which of course works only with a compatible GeForce graphics card. The prices start at 99 euros for the cable-bound 3D vision, for the wireless variant you have to plan 149 euros. Furthermore, a 3D-Vision-compatible 120 Hz monitor is required, such as the BenQ XL2410T (about 379 Euro).


The image transmission is normally carried out with 3D Vision via a dual-link capable DVI interface, corresponding cables are usually included with the monitor. Nvidia's operation has been extremely simple, it's enough to install the current driver, recognize 3D compatible games, and make the right settings automatically.


Also interesting are the two new 3D monitors from Acer: the GN245HQ (24 inches, price: 429 euros) and the HN274H (27 inches, price: 599 euros). In both monitors, the 3D vision receiver is inconspicuously integrated into the housing frame, and there is also a cable-connected Nvidia spectacle.