Virtual retinal display
As a virtual retinal display (VNA, English Virtual Retinal Display , retinal scan display , or retinal image display ) or light field display is called a display technology that a raster image directly onto the retina features of the eye. The user gets the impression of a canvas floating in front of him.
functionality
In the past, similar systems were produced that displayed an unfocused image directly in front of the user's eye on a small screen, mostly in the form of some kind of large sunglasses (see VR helmet ). The user focused their eyes on the background, making the screen appear to be floating. The disadvantage of these systems was the limited screen area, the heavy weight of the small screens that were used to generate images and the fact that the image only appeared sharp when the user focused his eyes to a certain depth. Due to the limited brightness of these systems, they were only suitable for indoor use.
Only recently did some innovations make real VNA systems usable. Above all, the development of light-emitting diodes with high brightness made the display bright enough to be able to use the devices outdoors during the day. In addition, adaptive optics allowed the devices to adapt dynamically to irregularities in the eye (but this is not necessary in every case). The result is a high-resolution display with excellent color gamut and brightness, far better than the best screens.
Most research in the field of VNAs has so far been carried out in combination with various virtual reality systems . In this role, VNAs have the advantage of being significantly smaller than existing screen-based systems. However, they share some of the same disadvantages as the need for optics to bring the image onto the retina. VNAs can also be used as part of a portable computer system.
Recently there has been some interest in VNAs for use in mobile devices such as cell phones, PDAs and various playback devices . In this role, the system would be placed in front of the user, e.g. B. on a table and directed at its eyes. The system would then recognize the eyes using face scanning and project the image into the correct location using motion compensation. The VNA offers unique advantages in this task, as it enables a conventional monitor to be simulated in a small device.