shutter glasses
In 3D movies, the three-dimensional representation is created by two slightly different images for the right and left eyes. The inertia of the eye interprets the different impressions or the sequential images into a stereoscopic representation.
For 3D projection, there are three optical separation methods with which different images are fed to the two eyes: The red- green technique, which dates back to the 1950s and uses color filter glasses; the polarized display with polarizing glasses, in which the images for the right eye are in different polarization planes; and the sequential display, in which the left and right eyes see different images alternately. The polarization technique can only be used for projections, not for 3D displays.
In sequential technology, one eye sees an image first, then the other. While one eye sees the image, the other eye cannot see any image and vice versa. The technique works with shutter glasses. The viewer alternately sees the image for one eye and then the image for the second eye through the shutter glasses. While the shutter glasses allow the image for one eye to pass through, they block the image for the other eye. Such glasses consist of Liquid Crystal Shutters( LCS) that are switched to pass or block.
To ensure that the switching of the two optics is synchronized with the 3D film, shutter glasses have a synchronization control. This can be switched with infrared light or with brightness information in the image. In the first case we speak of infrared shutter glasses, in the second case of white-light shutter glasses. The infrared-controlled glasses require their own control transmitter, whereas the white-light glasses interpret brightness information from the image. Shutter glasses are also used in virtual reality.