1. -Polarizers and 3-D effect

2. Polarization of light Light travels in waves. Some waves are traveling up and down, others are traveling side to side and every angle in between. Light polaroids act like a picket fence in the way of the wave. If the wave is going up and down, and the polaroid is up and down it will have no effect

3. But… If the wave is going side to side and the polariod is going up and down it will block the light out. up and down wave goes right through side to side wave The wave is blocked

4. If two polaroids are put at right angles to each other… No light can get through These block out side to side These block out up and down No waves can get through

5. Where are these used Certain low level reflections tend to come out polarized (all waves are up and down or side to side) So polarizing lens are used to block out these reflections. Cameras use them, and so do sunglasses (to block out sun glare at sunset or sunrise. LCD (liquid crystal display) are also polarized, you can check if your sunglasses are polarizers by looking at a digital watch display and tilting your head.

6. Newer 3-D movies also use light polarizers RealD 3D movies use light polarizers. The glasses are polarized. One lens goes up and down, the other right and left. Normal movies are projected at 24 frames per second (fps). RealD shows movies at 48 fps. A light polarizer flips constantly rotates 90 o with each frame. So each eye can see a different image at 24 fps

7. RealD The major advantage of this style to anaglyph (red/cyan glasses) is the ability to see colors as they are. This allows a true HD movie to be seen in 3 D The video is also more viewable without the glasses. If you have lost sight in one eye the movie appears normally in 2D where anaglyph would appear either red or cyan

8. TV’s Standard TV’s can not show movies that work with RealD technology because standard TV’s display at 30 fps Some TV’s have a higher frame rate (120 fps) to compensate for the difference between movie and TV frame rates. 3D TV also need the ability to polarize each frame displayed which standard TV’s don’t have.