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 Two pairs of RealD glasses demonstrating the polarization effect | |
| Type | 3D projection technology |
|---|---|
| Manufacturer | RealD |
| Website | http://www.reald.com  |
RealD 3D is a digitalstereoscopic projection technology made and sold byRealD. It is currently the most widely used technology for watching3D films in theaters.[1] Worldwide, RealD 3D is installed in more than 26,500 auditoriums by approximately 1,200 exhibitors in 72 countries as of June 2015.[2]
RealD 3D cinema technology is apolarized 3D system that usescircularly polarized light to producestereoscopic image projection. The advantage of circular polarization overlinear polarization is that viewers are able to tilt their head and look about the theater naturally without seeing double or darkened images.[3] However, as with other systems, any significant head tilt will result in incorrectparallax and prevent the brain from correctly fusing the stereoscopic images.
The high-resolution,digital cinema gradevideo projector alternately projects right-eye frames and left-eye frames, switching between them 144 times per second.[3] The projector is either aTexas InstrumentsDigital Light Processing device orSony's reflective LCOS (liquid crystal on silicon). A push-pullelectro-opticalliquid crystal modulator called aZScreen is placed immediately in front of the projector lens to alternately polarize each frame. It circularly polarizes the frames clockwise for the right eye and counter-clockwise for the left eye.[4] The audience wearscircularly polarized glasses that have oppositelypolarized lenses that ensures each eye sees only its designated frame. In RealD Cinema, each frame is projected three times to reduce flicker, a system called triple flash. The source video is usually produced at 24 frames per second per eye (total 48 frames/s), which may result in subtleghosting and stuttering on horizontal camera movements. Asilver screen is used to maintain the light polarization upon reflection and to reduce reflection loss to counter some of the significant light loss due to polarization filter absorption. The result is a 3D pictures that seems to extend behind and in front of the screen itself.[5]
