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16. Basic principle of large-viewing-angle micro-lens 3D display [ 65 ].
Figure 17. A Light Field 3D image is displayed on a state-of-the-art 3D screen manufactured by Looking Glass Factory. Multiple observation angles become visible depending on the viewer’ s real-world viewing angle [ 67 ].
particles using ultrasonic waves. The rapid movement of these particles creates a 3D image several centimeters wide, perceived by the naked eye as a swiftly shifting geometric form in the air.
In the report, lead researcher Ryuji Hirayama demonstrated programs that allowed him to control suspended particles – white blobs that rose and then hovered motionless in mid-air. With another tap, the blob transformed into a glowing butterfly, its wings still fluttering within the black box. Interestingly, the ultrasonic speakers not only create images but also produce sound and enable tactile sensations. When you touch the butterfly, you can feel a subtle vibration on your fingers. The speakers are positioned on both sides of the display, limiting the viewer’ s ability to interact with it and constraining the display’ s size. However, with hardware upgrades, Subramanian stated that a different type of sound wave could be used, allowing the speakers to generate images using only one side [ 59 ].
The fundamental approach of this display is fundamentally different from technologies like holograms, virtual reality, and polarized stereoscopic display. These familiar technologies rely on light to create an illusion of depth, providing viewers with a sense of realism. However, holograms can only be witnessed from specific angles, virtual reality and polarized stereoscopic display necessitate helmets or glasses, and all of these technologies can induce eye strain.