The reason why human vision can distinguish between near and far is the difference between the two eyes. The human eyes are separated by about 5 centimeters, and the angle of the two eyes will not be the same when looking at anything except aiming straight ahead. Although the gap is very small, but through the retina to the brain, the brain will use this tiny gap, to produce the depth of the distance, thus creating a sense of three-dimensional. Although one eye can see the object, it is not easy to distinguish the distance of the object near and far. According to this principle, if the same scene, with two eyes perspective gap to create two images, and then let the two eyes on one side, each see their own side of the image, through the retina can make the brain to produce a stereoscopic sense of depth of field. A variety of stereoscopic presentation technology, but also the use of this principle, we call it “polarization principle”. 3D stereoscopic film production has a variety of forms, which is more widely used is the polarized glasses method. It is the human eye to observe the scene of the method, the use of two side-by-side placement of the movie camera, respectively, on behalf of the human left and right eyes, synchronized filming of two slightly horizontal parallax of the movie screen. Screening, the two films were loaded into the left and right film projector, and in front of the projector lens were installed two polarizer axis of 90 degrees to each other polarizer. The two projectors need to synchronize the operation, at the same time, the picture will be put on the metal screen, the formation of the left image of the right like a double image. When the audience put on special polarized glasses, because the left and right polarizers of the polarization axis perpendicular to each other, and with the projector lens in front of the polarization axis; resulting in the audience’s left eye can only see the left image, the right eye can only see the right image, through the two eyes convergence function will be the left, the right image superimposed and in the retina, the cerebral nervous system to produce three-dimensional stereoscopic visual effects. Show a coherent three-dimensional picture, so that the audience feel the scene to the face, or into the deep recesses of the screen, can produce a strong sense of “immersive”. Watch 3D movie notes: 1, 3D movies are layered, so watch the movie is, be sure to follow the focus of the screen, do not look at the virtual fall out of the scene, in order to see the best results. 2, suffering from glaucoma, strabismus, severe astigmatism and other eye diseases is not suitable for watching 3D movies. Because of the 3D movie effect realistic, shocking, over 60 years old, children, pregnant women, heart disease and special diseases, please choose carefully. 3, 3D movie is different from the traditional two-dimensional film, the more forward the effect is more obvious; wear 3D glasses for a longer period of time, may increase the sense of fatigue. In the process of watching the movie, dizziness, vertigo, vomiting, tear phenomenon, please take off the glasses and head against the seat to rest for 1-2 minutes, can relieve fatigue, relax the nerves. 4, myopic friends if there are contact lenses, it is best to change before watching the movie, if not, you can only wear two glasses together, 3D glasses to wear outside, 3D glasses are larger and softer, can be fastened.