LCD shutter glasses are glasses used in conjunction with computers to create the illusion of a three dimensional image, an example of stereoscopy. Glass containing liquid crystal and a polarizing filter has the property that it becomes dark when voltage is applied, but otherwise is translucent. A pair of eyeglasses can be made using this material and connected to a computer video card. The video card alternately darkens over one eye, and then the other, in synchronization with the refresh rate of the monitor, while the monitor alternately displays different perspectives for each eye. This is called Alternate-frame sequencing. At sufficiently high refresh rates, the viewer's visual system does not notice the flickering, each eye receives a different image, and the effect is achieved. Stereo card image modified for crossed eye viewing View of Manhattan, c. ... Bold text Schlieren texture of Liquid Crystal nematic phase Liquid crystals are substances that exhibit a phase of matter that has properties between those of a conventional liquid, and those of a solid crystal. ... This article may be too technical for most readers to understand. ... A GeForce 4 4200-based graphics card A graphics card or video card is a component of a computer which is designed to convert a logical representation of an image stored in memory to a signal that can be used as input for a display medium, most often a monitor... The refresh rate (or vertical refresh rate, vertical scan rate) is the maximum number of frames that can be displayed on a monitor (or television) in a second, expressed in hertz. ... Nineteen inch (48 cm) CRT computer monitor A computer display, monitor or screen is a computer peripheral device capable of showing characters and/or still or moving images generated by a computer and processed by a graphics card. ... Alternate-frame squencing (sometimes called Alternate Image, or AI) is a method of showing 3-D film that is used in some venues. ...

The problems associated are the cost for the additional equipment (typically up to US$100), and that the flickering can be noticeable if the refresh rate is not sufficiently high, as each eye is effectively receiving only half of the monitor's actual refresh rate. As with other single image methods the brightness is considerably diminished.

Another possible effect is "ghosting". Since the opaque phase of the LC still permits a small amount of light to transmit, some users experience secondary "ghost" images from the alternate channel. This effect can be exacerbated by persistance effects in the phosphors of the CRT, causing images to "bleed" over into the other channel.

Until recently, the method only worked with CRT monitors; modern flat-panel monitors now support high enough refresh rates to work with some LC shutter systems. Cathode ray tube employing electromagnetic focus and deflection Cutaway rendering of a color CRT The cathode ray tube or CRT, invented by Karl Ferdinand Braun, is the display device that was traditionally used in most computer displays, video monitors, televisions, radar displays and oscilloscopes. ... Liquid crystal display television is, as indicated by its name, a television using LCD technology (generally TFT), as opposed to cathode ray or plasma for its visual output. ...