Up to the time of this paper published, three different 3D displays has been researched and tested. Figure 6 shows a side view of the 3D display called Planar. It consists of 2 AMLCD display and a 50/50 mirror between. The top AMLCD is horizontally-linear polarized and the lower AMLCD is vertically-linear polarized. The 50/50 mirror would reflect 50% of light intensity from both the top and bottom screen. User would require wearing 3D glasses, which left eye is polarized horizontally and right eye is polarized vertically. Therefore, one LCD image would only enter one of the users eye, resulting a stereo vision.
Figure 6. Planar Side View
The second 3D display is the Zalman. Unlike the Planar, Zalman uses circular polarization and only have one screen. The idea is that each row of pixel is circularly polarized in opposite direction. The odd number of pixel row is clockwise direction and the even number of pixel row is anti-clockwise direction. The pixel grid in the other word is horizontally interlaced. It is a common but expansive method of creating stereo image. User would require wearing circular polarised glasses.
The main advantages of using Planar are the high quality image and viewing angles. Users get full LCD resolution with Planar whereas only half of the resolution with Zalman. The problem with Planar is that it loses it stereo vision if user head movement rotates along their viewing axis. On the other hand, Zalman uses circular polarization which does not suffer this problem.
The third 3D display system is using two projectors with circular polarizer. One projector has clockwise polarizer and other one has anti-clockwise polarizer. Circular polarised glasses are required for user. This system would give us high quality image without suffering rotational problem like the planar. The difficulty is the installing of the projectors, calibrations as well as prices.