1. What is it about

You were still in wonder of the latest gadget you were wearing. It’s a lot lighter than your current head-mounted-display, but that’s not what has impressed you most. It’s the clarity! Everything looks so natural. You can see overlaid computer generated visuals even at the periphery of your eyes. It’s as if the overlaid features belong to the scene. The effect is even more noticeable as you move your head around. With your head-mounted-display you could only see objects when they entered the display in front of your eyes as you looked towards them and you always struggled with focus. Despite great advances since the early days, it seemed they still couldn’t get the hang of it. But now, this retinal display was such a joy to use.

Virtual retinal display works by drawing a laser raster display directly on your retina. You get to see a conventional display in front of your eyes with a large field of view. If carried out accurately, you won’t be able to tell the difference from what you see normally. Ultimately, there will be no edges, no flicker, no sense of looking at a computer display.

2. Where is the fun

• Being able to see the real world, integrated 3D objects and overlaid 2D information, correctly focused and over 180º field of view.
• Giving a presentation while extra information is streamed to your eyes in real time.
• Being able to see extra notes you made for yourself that no one else can see anywhere you are can make your interactions more efficient. Having a negotiation meeting will be whole new ballgame.
• Being able to know you are about to bump into your friend in the shopping centre, in just about 20 seconds as your friend’s icon is displayed on you left, even though he is still behind the wall. Oh, by the way, she may also be able to see you, so once this technology is mainstream, it may not be that easy to avoid someone you don’t want to meet!
• The largest screen viewable by a human is, by definition, what we naturally can see at almost 180º field of view. The holy grail of display technology. Retinal display has the theoretical capability to deliver this.

3. What are its Applications

• Once this technology is established, it can become a critical component of wearable computing.
• This technology can also replace all other types of display mechanism. You may not even need to have a device attached to your head. Instead of having a monitor, you may setup this retinal display on your desk which will use a camera to target your eyes and injects the laser beams directly into your eyes even when you move your head around. With clever positioning algorithms, you can get the illusion that the display is fixed to your desk and does not move as you move your head.
• There is strong interest for military applications where situational awareness is critical. Information about location of friendly and enemy units can be overlaid on the real world scene in addition to other information such as guidelines, routes to take and critical stats.
• Mobile phone and personal communication industry can benefit greatly from this technology. Currently the display sizes are small and when you are mobile, it is difficult to get the same experience as using a standard PC.

4. How developed is it

This technology is still in its infancy and although there has been some progress, it is still early days. A great introduction to retinal virtual displays and another article walk you through the capabilities of the human eye and how this system works in principle. One of the pioneers of this technology is Microvision who are currently involved in the research and development of the laser system required for this device to function.

Interestingly, based on the number and density of rods and cons in you retina (light and colour sensors), you only need a resolution of 8400 x 5400 to get an optimal display projected into your eyes. Currently, the highest resolution you can get HD-DVD is about 1920 x 1080. Ultra high definition video which is in research stage can offer 7680 x 4320 with extremely high bandwidth requirements. Hence, there is long way ahead of us before we can get true artificial retinal vision.

A related technology derived from this research is micro projectors. Instead of projecting the laser into the retina, they can be projected into flat surfaces such as walls for a large display. You can point your mobile phone to a wall to see a much larger screen displayed on the wall. This is certainly revolutionizing and will most probably be adopted much sooner than the virtual retinal displays.

And of course, another way to project an image to a retina is by visual implants. Some progress has been made in this regard, though their use will be very slow to pick up. Like all other implants that require surgery, these devices may not become mainstream since humans are wary of modifying their bodies with un-natural gadgets with potential health consequences.

5. How can it be improved

For retinal displays to become more competitive than traditional displays or head-mounted-displays, they need overcome two great challenges among others:

• The ability to focus the raster scan correctly onto the retina in real time despite movements of the eye, head or even the device itself. This requires adaptive control, sophisticated machine vision techniques, and precise eye-safe laser.
• The wearable device should be light and comfortable to use with minimal impact on everyday activities.

Clearly, much work is still necessary before we can even start addressing these challenges.

6. What does it lead to

• Retinal display’s greatest capability is to draw separate images for each of your eyes, ultimately creating a 3D vision with your natural field of view which will be indistinguishable from reality. Now, that’s something worth waiting for!
• Over time, the device can become smaller and smaller where one may simply wear it at all times. This leads to having access to a wide range of real time data streamed directly into your eyes.
• Widget industry will become bigger in the future. Widgets will be shown on anything that is capable of displaying digital content. Everyone will have their own custom widget layout used to access all sorts of information. Beauty, elegance and efficiency will be critical factors in designing these widgets. Every pixel counts and there will be a competition between widgets to occupy the most watched pixel-spaces. Retinal displays will be no exception. In fact, widgets will be extremely useful since you want to access frequently used information with minimal effort. You can have multiple modes. Use can use one mode when you are out, which shows you relevant information such as weather and maps. In another mode when you are at home, you may use a set of widgets that show information about your baby, food-ordering, etc, and again another mode for business meetings.

Once this technology becomes main stream, almost all other types of displays may be overshadowed. Other popular forms of displays might be large flexible displays used for billboards, concerts and the like.