3D display using intersection of light beams

Conventional stereoscopic displays yield conflicts between convergence and accommodation of the human eyes. It is said that, if the conflicts are too severe, they may cause visual stress to the human. We propose a new 3D display with great potential to reduce such conflicts and visual stress. It presents 3D images by reconstructing points in 3D space as the intersection points of multiple thin light beams. The intersection points are perceived as light sources in 3D space by observers. Multiple beams striking the observer's eye generate 3D images that are more natural for the observer than conventional stereoscopic images. A prototype device was manufactured comprising of a 2D LED matrix, a collimator lens and a spatial light modulator that generates small apertures so as to convert thick light beams into thin light beams. By controlling the distribution and intensity of light sources in synchronization with the position of the aperture, a number of intersection points of light beams in space can be formed. With this prototype, the accommodation of the eyes of observers was investigated while they were viewing reconstructed 3D images. As a result, we found that, when the observers viewed a reconstructed 3D image with both eyes, their eyes' accommodation and convergence corresponded to depth information. This is an effect which conventional stereoscopic display cannot realize.