View source for Virtual retinal display

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{{More citations needed|date=August 2009}}
{{short description|Display technology}}
[[File:Virtual Retinal Display Diagram.svg|thumb|right|300px|A diagram showing the workings of the virtual retinal display]]
A '''virtual retinal display''' ('''VRD'''), also known as a '''retinal scan display''' ('''RSD''') or '''retinal projector''' ('''RP'''), is a display technology that draws a [[raster graphics|raster]] display (like a [[television]]) directly onto the [[retina]] of the eye.

== History ==
In the past similar systems have been made by projecting a defocused image directly in front of the user's eye on a small "screen", normally in the form of large glasses. The user focused their eyes on the background, where the screen appeared to be floating. The disadvantage of these systems was the limited area covered by the "screen", the high weight of the small televisions used to project the display, and the fact that the image would appear focused only if the user was focusing at a particular "depth". Limited brightness made them useful only in indoor settings as well.{{Citation needed|date=May 2018}}

Only recently a number of developments have made a true VRD system practical. In particular the development of high-brightness [[LED]]s have made the displays bright enough to be used during the day, and [[adaptive optics]] have allowed systems to dynamically correct for irregularities in the eye (although this is not always needed). The result is a high-resolution [[screenless video|screenless]] display with excellent [[color gamut]] and brightness, far better than the best television technologies.

The VRD was invented by Kazuo Yoshinaka of Nippon Electric Co. in 1986.<ref>DISPLAY DEVICE published 1986-09-03 (Japanese publication number JP61198892)</ref>  Later work at the [[University of Washington]] in the [[Human Interface Technology Lab]] resulted in a similar system in 1991.<ref>{{cite journal | title=The virtual retinal display: a new technology for virtual reality and augmented vision in medicine. | author=Viirre E, Pryor H, Nagata S, Furness TA 3rd | journal=Stud Health Technol Inform | series=Studies in Health Technology and Informatics | year=1998 | volume=50 | issue=Medicine Meets Virtual Reality | pages=252–257 | doi=10.3233/978-1-60750-894-6-252 | pmid=10180549}}</ref> Most of the research into VRDs to date has been in combination with various [[virtual reality]] systems. In this role VRDs have the potential advantage of being much smaller than existing television-based systems. They share some of the same disadvantages however, requiring some sort of optics to send the image into the eye, typically similar to the sunglasses system used with previous technologies. It also can be used as part of a [[wearable computer]] system.<ref>[http://www.hitl.washington.edu/projects/vrd/ Virtual Retinal Display (VRD) Group]</ref>
 
A Washington-based startup, MicroVision, Inc., has sought to commercialize VRD. Founded in 1993, MicroVision's early development work was financed by US government defense contracts and resulted in the prototype [[head-mounted display]] called Nomad.<ref>{{cite web|author=DQC BUREAU|date=June 16, 2004|title=VIRTUAL RETINAL DISPLAY: Your Eye Is The Screen |url=http://www.dqchannels.com/virtual-retinal-display-your-eye-is-the-screen/}}</ref><ref>{{cite web|work=Photonics Media|title=Microvision Ships Nomad Personal Display Systems|url=http://www.photonics.com/Article.aspx?AID=11502}}</ref>

In 2018, [[Intel]] announced Vaunt, a set of [[smart glasses]] that are designed to appear like conventional glasses, which use retinal projection via a [[vertical-cavity surface-emitting laser]] and [[holographic grating]].<ref>{{Cite web | url=https://www.theverge.com/2018/2/5/16966530/intel-vaunt-smart-glasses-announced-ar-video |title = Intel is making smart glasses that actually look good|date = 5 February 2018}}</ref> Intel gave up on this project,<ref>{{Cite web|url=https://www.theverge.com/2018/4/18/17255354/intel-vaunt-shut-down|title=Intel is giving up on its smart glasses|last=Bohn|first=Dieter|date=2018-04-18|website=The Verge|access-date=2019-07-16}}</ref> and sold the technology to North.<ref>{{Cite web|url=https://www.theverge.com/2018/12/17/18144221/north-focals-intel-vaunt-patents-ar-glasses|title=North has acquired the patents and tech behind Intel's Vaunt AR glasses|last=Bohn|first=Dieter|date=2018-12-17|website=The Verge|access-date=2019-07-16}}</ref>

In the same year, QD Laser, a Japanese laser maker spun off from [[Fujitsu]], developed the first commercialized true VRD RETISSA Display. In the following year, the firm started to sell the successor VRD RETISSA Display II, which featured a higher resolution equivalent to 720p.<ref>{{Cite web|url=https://vrinside.jp/news/post-176232/|title=網膜に直接映像を照射！新しいカタチのARグラス「RETISSA(R) Display II」登場|date=2020-03-12|website=VRInside|access-date=2020-04-02|lang=Japanese}}</ref>

In 2023 Sony produced a compact camera with an integrated Retissa Neoviewer retinal projection device, for release in the US. The resolution of the retinal display only (not the camera) is claimed by the manufacturers to be nominally equivalent to 720P.<ref>See: [https://retissa.biz/en/retissa-neoviewer QD Laser Product page for RETISSA NEOVIEWER] and also [https://electronics.sony.com/imaging/compact-cameras/all-vlog-compact-cameras/p/dschx99rnvkit SONY's HX99 RNV Retina Projection Camera kit product page].</ref> 

Although "not a medical device" it is hoped that the retinal projection viewer may be of particular value to some visually impaired users, and the adaptation was heavily subsidised by Sony. Because of the novel user experience, and limited availability, potential buyers were strongly encouraged to participate in  "touch-and-try" events to see if the technology is useful to their particular circumstances before committing to a purchase.<ref>{{Cite web |author1=Chris George |date=2023-07-25 |title=Sony's new compact camera brings photography to the visually impaired |url=https://www.digitalcameraworld.com/news/sonys-new-compact-camera-brings-photography-to-the-visually-impaired |access-date=2024-01-04 |website=digitalcameraworld |language=en}}</ref>

== See also ==
* [[Augmented reality]]
* [[Bionic contact lens]]
* [[Google Glass]]
* [[Head-up display]]
* [[List of emerging technologies]]
* [[Magic Leap]]
* [[Optical head-mounted display]]
* ''[[Physics of the Future]]''
* [[Smartglasses]]
* [[Visual prosthetic]]

== References ==
{{reflist|30em}}

== External links ==
* [http://www.hitl.washington.edu/projects/vrd/anim/Mov.htm Animations of how a VRD works]
*  {{Cite news |url=https://spectrum.ieee.org/in-the-eye-of-the-beholder |title=In the Eye of the Beholder |first=John R. |last=Lewis |date=May 2004 |work=[[IEEE Spectrum]]}}

{{Mixed reality}}
{{Stereoscopy}}
{{emerging technologies|displays=yes}}

{{DEFAULTSORT:Virtual Retinal Display}}
[[Category:Display technology]]
[[Category:Multimodal interaction]]
[[Category:Virtual reality]]
[[Category:Mixed reality]]
[[Category:Japanese inventions]]