A new display technology was developed that allows people to see 3D holographic images and videos through a wide viewing angle without wearing 3D glasses.
A team of researchers led by Park Yong-keun, a professor at the KAIST announced on January 24 that they developed a 3D holographic display that has more than doubled the size of a 3D holographic image and expanded a viewing angle more than ten-fold by controlling the scattering of light.
3D holograms, which often appear in science fiction films, are created using computer graphics effects, and there are limitations in realizing them with current technology in good truth. For this reason, research on virtual reality (VR) and augmented reality (AR) using an optical illusion that projects two different two-dimensional images at the eyes instead of a three-dimensional image is actively conducted.
To create a three-dimensional hologram that can be viewed without 3D glasses, directions of light must be changed using an optical control device (spatial light wave front controller) that precisely controls the direction of light propagation. However, since the number of pixels of the spatial light wave front controller is too small, it cannot be used as a three-dimensional display. Even if a spatial light wave front controller is used, a 3D image size is 1 cm and viewing angle is within 3 degrees, defying commercialization.
In addition to a spatial light wave front controller, the researchers used scattered light to control the scattered light by using ground glass (glass which is translucent as it was ground) to enlarge the image size and viewing angle.
The team succeeded in producing a three-dimensional hologram with a width of about 2 cm, a height of about 2 cm, and a viewable angle of about 35 degrees. The researchers explained that the spatial bandwidth (hologram size x viewable angle) is more than 2,600 times better than that of the existing technology. "We properly made use of the scattering of light considered to impede people’s recognition of objects. We hope that this study will lay the foundation for the practical use of displays that can be seen without special glasses," Yoo Hyun-seung, a doctorate degree candidate who is a primary author of the thesis. The results of the study were published on the January 24 online edition of "Nature Photonics", an international scientific journal in the field of optics.