-Polarizers and 3-D effect-Polarizers and 3-D effect

Polarization of lightPolarization of light

Light travels in waves.Light travels in waves.

Some waves are traveling up and Some waves are traveling up and down, others are traveling side to side down, others are traveling side to side and every angle in between.and every angle in between.

Light polaroids act like a picket fence in Light polaroids act like a picket fence in the way of the wave.the way of the wave.

If the wave is going up and down, and If the wave is going up and down, and the polaroid is up and down it will have the polaroid is up and down it will have no effectno effect

But…But…

If the wave is going side to side and the If the wave is going side to side and the polariod is going up and down it will block polariod is going up and down it will block the light out.the light out.

up and down wave

goes right through

side to side wave

The wave is blocked

If two polaroids are put at right If two polaroids are put at right angles to each other…angles to each other…

No light can get throughNo light can get through

These block out side to side

These block out up and down

No waves can get through

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

Newer 3-D movies also use light Newer 3-D movies also use light polarizerspolarizers

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

RealDRealD

The major advantage of this style to The major advantage of this style to anaglyph (red/cyan glasses) is the ability anaglyph (red/cyan glasses) is the ability to see colors as they are. to see colors as they are. This allows a true HD movie to be seen in This allows a true HD movie to be seen in 3 D3 DThe video is also more viewable without The video is also more viewable without the glasses.the glasses.If you have lost sight in one eye the movie If you have lost sight in one eye the movie appears normally in 2D where anaglyph appears normally in 2D where anaglyph would appear either red or cyanwould appear either red or cyan

TV’sTV’sStandard TV’s can not show movies that Standard TV’s can not show movies that work with RealD technology because work with RealD technology because standard TV’s display at 30 fpsstandard TV’s display at 30 fps

Some TV’s have a higher frame rate (120 Some TV’s have a higher frame rate (120 fps) to compensate for the difference fps) to compensate for the difference between movie and TV frame rates.between movie and TV frame rates.

3D TV also need the ability to polarize 3D TV also need the ability to polarize each frame displayed which standard TV’s each frame displayed which standard TV’s don’t have.don’t have.