Curious how the displays in augmented reality headsets work? We will explore 5 technologies that are breaking new ground in AR usability.
Let's talk about near-eye technology, the key to understanding how augmented reality (AR) headsets work. To get a handle on why this field is so vast and intriguing, we need to take a step back and talk about some core ideas with respect to technological development.
If you were to be teleported back to the 16th or 17th century into a cornfield, you'd have no idea what you were looking at. Corn stalks used to be planted many feet apart, as they were unable to support their own weight. This means they sagged onto the ground, lying almost flat.
So instead of nice, neat rows of lush green leaves, you'd be looking at thousands of humps of limp green and yellow plants – almost like poorly watered vines – against a backdrop of mostly brown.
There was a fundamental limitation to the ability to grow corn – and, before the 19th century, more or less any plant – in abundance. That limitation was the strength of the stalk. But scientists overcame this fundamental limitation through research, development and patience. They eventually developed genetic-splicing and cross-pollination techniques that allow for the tightly packed cornfields we see in places like Nebraska and Illinois today.
Why do we care about this, if we're talking about near-eye technology and augmented reality?
There is a fundamental limitation to the human eye that is currently being overcome with fascinating technology today – and it's opening up a large range of possibilities.
The human eye has a range of about thirty degrees to its peripheral. Outside of that, one can only "sense" objects, as opposed to making out details. In "regular" reality, this poses few threats to our understanding of information input. But in things like virtual reality (VR) and AR, this poses a problem.
Glasses have an angle wider than thirty degrees. In fact, many glasses get close to 180. This is a problem, as the difference between what you can see and what is in front of your eye is about 150 degrees. (This is admittedly an oversimplification, but you didn't click on this article to get into the intricacies of optical theory, did you?)
To be clear, in assisted reality (aR) this isn't much of a problem. aR devices simply give access to information – the information doesn't have to respond to the user's environment. This means a set of aR glasses can simply display a screen that adjusts to your eyes by adjusting to the 150-degree difference in a linear fashion.
But this used to cause all kinds of problems in augmented reality, as the angle you're using within the 30-degree range is constantly changing.
A swathe of technical solutions has been discovered in the last 30 years to overcome this problem.
In short, there are a few ways to get a virtual environment overlaid on a set of glasses. For the sake of your sanity – and because you can go on your own YouTube deep dive later – we'll look at the five major players in the industry.
Incoupling
Incoupling refers to a technique that allows one set of lenses to be embedded in another. If you watch the video below, you'll see a small lens inside the larger lens worn by the occupant, which then allows the image to be overlaid onto the surrounding environment.
This sort of technology takes a lot of planning and synchronicity, considering the tracking software. Many of these headsets with lenses use a motor to keep the image in line with pupils as they dart across the field of the larger lens. They also use tracking outside of the headset to ensure the image overlaid to the environment adjusts as the user walks around.
Half-silvered mirrors
This is the same technology that's used in two-way mirrors – the kind that is common in police stations. This allows an image to be projected onto a lens, which is then reflected into the eye. We won't get into all the physics but, from an engineering standpoint, you essentially only coat one side of a glass with the material used to make a mirror. The optimum advantage of this solution is weight, as some of the other options for augmented projection can weigh the glasses down slightly.
The drawback here is that the projection is hard to project, and has difficulty being overlaid onto specific parts of an environment. For instance, if you're using augmented reality to display construction parameters, it's hard to know whether things will be laid over with precision.
Tiles
As your eye moves, you're looking at different spots on your glasses. The tiling approach to augmented lenses takes advantage of this by projecting an image into each small tile. There are many of these tiles connected across the lens, so no matter where your eye hits, you see the image. The advantages of this approach are clarity of vision and ease of construction.
Waveguides
This is probably the most fascinating technology on this list. Waveguides inlay prisms into the structure of the lens itself so that the light sent to the display is guided across the glass to end up where it needs to go. A motor will sometimes track eye movement on these models for maximum efficiency.
Retina projection
This is the last, and possibly most intense method on this list. Retina projection is exactly what it sounds like: projecting an image using a very finely tuned projector right through the pupil and onto the retina. This has obvious advantages for precision and affordability.
It might seem a little odd to imagine images being projected into your eyes, but this is far from far-flung technology. In fact, Apple is rumoured to be considering the technique for its upcoming AR glasses.
Conclusion
Paradigm shifts in near-eye technology are already happening. The technology becomes cheaper, more durable and more integral to the workplace environment by the day. Waveguide technology seems to be the most promising for future iterations of smart headsets. And, indeed, the tech already appears in devices from Vuzix, Microsoft and Magic Leap.
It's prudent to incorporate these headsets into the workplace culture now, so they are built into the infrastructure of your business as they become more ubiquitous. Luckily, there are many exciting options to choose from. Browse our XR devices online to see some for yourself.
