Virtual retinal display (VRD) is a novel display technology that scans light directly onto the retina to create high resolution images without the need for a screen. It works by using light-emitting diodes or lasers to project pixelated images in raster patterns onto the retina. Key advantages of VRDs include their small size, high resolution, wide field of view, and potential applications in areas like medicine, aviation, and augmented reality. Future developments may make VRDs more compact and affordable for widespread use.

1. VIRTUAL RETINAL DISPLAYVIRTUAL RETINAL DISPLAY
SUBIN C ANTONY
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2. INTRODUCTIONINTRODUCTION
 PDD under development in HIT lab,
University of Washington.
 Not a screen based technology.
 Scans light directly on to retina of eye.
(Hence the name )
 Full colour, high resolution, high
brightness wide field of view virtualbrightness, wide field of view virtual
display without flickering.
 Potential applications include HMDs for Potential applications include HMDs for
military, aerospace, engineering, medical
fields.
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3. VRD BasicsVRD BasicsVRD BasicsVRD Basics
Substitute to conventional bulky and power
h VDUhungry VDUs.
Light is focused to a miniscule image(frame)
on retinaon retina.
SLD or LED triads of R,G&B emits light.
Mixing in proportions can produce anyg p p p y
colour.
As light scans the retina, it is intensity
d l t d b th id i lmodulated by the video signal.
Scanning is performed directly onto retina in
a raster pattern through collimating opticsa raster pattern through collimating optics.
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4. Above figure is the basic block diagram of VRDAbove figure is the basic block diagram of VRD
As shown, the viewer perceives a wide field of view
image as if from a screen placed some distance away.
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5. Key features of VRDKey features of VRDKey features of VRDKey features of VRD
 Size and Weight: Small size as no intermediate screen is
t All t ll d li ht ki it hi hlpresent. All components are small and light making it highly
portable. Appropriate for Hand held and Head mount displays.
 Power consumption: Light sources consume very less
power in order of milli watts. Scanning is done with a resonant
device (MRS) with high figure of merit. Exit pupil of VRD has
very small aperture allowing generated light to enter eyes almost
l l H hi h ffi icompletely. Hence high power efficiency.
 Resolution: Limited only by diffraction and optical aberration
in the optical components, limits in scanning frequency and
modulation b/w of photon source. SLD is a coherent source and
offer high modulation b/w to give resolutions well over a million
pixels. State of the art scanners can scan over a1000 lines per
f hi h i bl HDTVframe which is comparable to HDTV.
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6.  Brightness: Perceived brightness is only limited by power of the
li ht SLD id d b i ht l llight source. SLD sources can provide very good brightness levels
even for see through mode in day light.
 Field of view: Inclusive systems provide horizontal field of
view b/w 60-100 degrees. See through mode systems have it
slightly over 40 degrees. These figures are far better than existing
HMD systems.
 Stereoscopic display: Supports stereoscopic display as both
eyes can be separately addressed. Thus provides a good
approximation to natural vision.
 Inclusive & See through: See through works very well even at
very high illumination conditions of about 10000 candella per meter
squared.q
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7. VRD System OverviewVRD System OverviewVRD System OverviewVRD System Overview
A block diagram of a VRD system is shown below
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8. ApplicationsApplicationsApplicationsApplications
VRDs can reduce the read-time and can act as always-present
guides for many tasks.
The various fields of application of VRD technology are listed.
 Radiology
 Surgery Surgery
 Therapeutics (Scanning Laser Ophthalmoscope)
 Production
 Communication
 Augmented Virtual reality
 Aerospacep
 Military
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9. Future scopeFuture scopeFuture scopeFuture scope
 When cost of production falls further, we will see VRDs
f lfilli f i d li i dfulfilling many functions and applications, and may
perhaps see a time where they become ubiquitous in the
more distant future.
 Future systems will be even more compact with the
advent of MEMS(Micro Electro Mechanical System)
i i t l di d d li ti ifiscanners, miniature laser diodes and application specific
IC technology.
 Another key development to come is the advent ofy p
Augmented Reality display systems to assist people in
their various tasks.
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10. ConclusionConclusionConclusionConclusion
VRD provides an unprecedented way to stream photons
h f h ff di hi h l ito the receptors of the eye; affording higher resolution,
increased luminance, and potentially a wider field-of-
view than all previous displays. Virtual retinal display isp p y p y
a breakthrough in imaging technology that will
optimally couple human vision to the computer. Cost is
currently acting as a blocker of the technology in mostcurrently acting as a blocker of the technology in most
industries. If this continues to fall, we will see VRDs
fulfill many functions and applications, and may perhaps
h h b i bi i i fwatch them becoming ubiquitous in near future.
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