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Using Cellophane For 3D Displays On Your Laptop
prestidigital writes "From the abstract:
[the authors] present a novel, inexpensive, stereoscopic technique for generating 3D displays from cellophane and a laptop computer screen.
(Once again my physnews update sends me email that doesn't suck!)"
No, this is science.
The unofficial
This technique does not, however, protect your servers from a severe /.ing! 30 comments and already down... Woo hoo! Way to go guys!
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Using cellophane to convert a laptop computer screen into a three-dimensional display Keigo lizuka Department of Electrical & Computer Engineering 35 St. George Street University of Toronto Toronto, Ontario, Canada M5S 1A4 Abstract We present a novel, inexpensive, stereoscopic technique for generating 3D displays from cellophane and a laptop computer screen. Stereoscopy requires independent manipulation of the left and right eye views.1 Our technique takes advantage of two facts; the first is that the light from the liquid crystal display of a laptop computer is polarized light 2, and therefore we can easily manipulate its transmission with a polarizer sheet. The second fact is that a cellophane half-waveplate can change the direction of polarization of light. The direction of polarization of one half of the laptop screen was rotated by the cellophane half-waveplate. Two images displayed with orthogonal polarization on two halves of the screen become separable by wearing a pair of glasses of orthogonal polarization. A distinct advantage of our technique is its simplicity; a laptop screen can be converted into a 3D display with minimal knowledge of optics. An additional advantage of our technique is that we can eliminate the need for the observer to wear special glasses by making the computer wear the glasses instead. This is possible because a laptop computer normally has only one viewer at a time, and the relative orientation of the viewer's head and the laptop screen is sufficiently stationary. A further significant discovery is that we verified that cellophane (costing mere pennies) proved to be a better half-waveplate than a commercial half-waveplate (costing hundreds of dollars for the required size) for rotating the polarization of white light. 1. Properties of cellophane Let us begin by examining the properties of cellophane. Cellophane is fabricated by protruding an alkaline viscose solution through a narrow die into an acid bath. Because of the unidirectional strain during the protruding process, cellophane is an anisotropic material and it behaves like a calcite crystal. The refractive index ny of cellophane measured by a light wave component polarized in the direction of the longer dimension of the rolled cellophane (in the y direction) is larger than nx, measured by a light wave component polarized in the direction of the shorter dimension (in the x direction). As a result, the component polarized in the x direction propagates through the medium faster than the component polarized in the y direction. After transmission through such a medium, a phase difference arises between these two light wave components. The difference ny-nx in the refractive index and the thickness of the cellophane determine the amount of the phase difference between the components polarized in the x and y directions. A medium that creates a 180o phase delay is a half-waveplate. The phase difference incurred in plain ordinary colorless cellophane (our sample had a thickness of 25 microns was measured to be 170.2o , which is about 95% of the phase delay of an ideal half-waveplate. These measured results are within acceptable limits for a number of practical applications that do not require a precise 180o phase delay. Having demonstrated the feasibility of using cellophane as a half-waveplate, we now examine what a half-waveplate does and how it can be used to create a 3D display. One of the most important functions of a half-waveplate is its ability to rotate the direction of polarization of the transmitted light. We found that cellophane's performance in rotating the direction of polarization of white light was superior to that of a commercially available half-waveplate designed for a specific wavelength. An added bonus is that cellophane is very inexpensive. Before describing the role of a half-waveplate in generating 3D images, we need to introduce some basic stereoscopic principles. 2. Stereoscopic principles Figure 1 explains the basic principle of a 3D display based upon the parallax effect1. (a) (b) (c) The observer se
Does this mean that Nokia will come out with a cool new cellophone with one of these 3-d saranwrap displays?
Don't blame Durga. I voted for Centauri.