3D display goes deeper

When it comes to three-dimensional displays, there are usually compromises. Some methods have narrow viewpoints that require a user to view the image from directly in front of a screen. Some methods require that the user look through special glasses. Other methods don't provide a lot of depth.

Researchers from Seoul National University in Korea have found a way to deepen one type of three-dimensional display method -- integral imaging -- that has historically suffered from relatively shallow depth, but does not require users to wear glasses.

The method could eventually be used to make three-dimensional billboards and three-dimensional television.

The method makes images appear at three distinct depths by controlling the polarization and direction of the light rays that the display generates. The researchers' prototype display contains a polarizer and sliding slit mask, a calcite crystal, and an array of lenses.

The polarizer switches the display's light among vertically polarized, horizontally polarized and unpolarized light more quickly than the eye can detect. The crystal changes the angles at which the two types of polarized light travel to the lenses. This causes the three types of light to focus at three different depths.

The method could be used for applications like three-dimensional advertisements in five years, and in three-dimensional television in 10 or more years, according to the researchers. The work appeared in the August 11, 2003 issue of Optics Express.