Researchers at Canada's Queen's University Human Media Lab developed a prototype phone called HoloFlex that use a holographic lightfield 3D display that can "project" 3D images.
The HoloFlex uses a flexible 5.5" Full-HD (403 PPI) OLED display (seems to be the same LGD panel used in the G Flex 2) with a 3D-printed flexible lens-array on top, that forms a 160x104 matrix (16,640 lenses). Each lens projects the 12 pixel-wide circular area directly underneath it out into space.
Each lens projects a slightly different view of the same scene - which together makes a 160x104 3D image about a full scene over a field of view of about 35 degrees. All this means that HoloFlex can transform software models into lightfield display-based holograms, resulting in images that have depth and exhibit motion parallax and can be viewed from multiple perspectives by multiple users.
The researchers say that this is one of the smallest and most mobile lightfield displays ever developed. The main challenge towards commercialization is, in fact, the 3D printed micro-lens array.