Greenlight Insights, a company specializing in XR technology market intelligence and organizer of xRS Week, together with Adlens, a company developing adaptive lenses, recently released a study on optics in XR. The paper looks at optical issues in XR and the solutions companies are developing to solve them. It also looks at how and when these developments are likely to impact the XR technology market.
“The optical interface holds the key to unlocking the potential of AR to come into arms reach and become truly interactive,” according to the report authors.
The Optical Interface
The greatest barriers to large scale adoption of advanced XR technology are optical problems. The human eye has evolved to see things in the natural world, meaning that sometimes augmenting that world is taxing to the eye. This limits the effectiveness of XR technology and how long people can effectively use it.
Specifically, the whitepaper, titled “Optics in Focus: The Vital Role of the Optical Interface in Unlocking the True Potential of Augmented Reality”, discussed vergence-accommodation conflict (VAC) and focal rivalry.
VAC occurs because the eyes change orientation to view things at different distances. However, in XR displays, things can appear several feet away despite the display being within inches of the eyes. This makes AR – and to a lesser extent, VR- uncomfortable to use for extended periods.
Focal rivalry is more a problem for AR because it involves super-imposing digital objects over the natural environment. Because the display is closer to the eyes than the natural environment, one or the other is in poorer focus.
So far, the solutions to these problems from even advanced XR technology companies remain archaic.
One example is always scaling and placing a digital image such that it appears to be several feet from the user. This reduces the issues to some extent but poses its own problems.
One of the more obvious problems comes in cases in which AR is used in small spaces. Another problem comes with AR applications that use gesture controls. Gesture control is supposed to – and has the potential to – make interactions more natural. However, it has much the opposite effect when the AR model appears out of arm’s reach. Suddenly, gesture controls feel less like holding an object and more like using supernatural powers. In some applications, the effect is fun and even desirable. In other, more practical applications, it takes away from the experience.
So far, there are two more advanced solutions to these problems currently on the market. For example, Varjo’s XR1 uses Visual Pass-Through (VPT) systems. This technology digitally renders the real-world environment around the digital model. This essentially creates a real-world-based VR environment. That reduces problems with both VAC and focal rivalry. It comes at a cost, however. No XR technology has yet achieved field of view (FOV) equal to that of the human eye. In the case of VPS, this results in breaks in the display where the field of view ends.
The other solution is adaptive lenses. While there are different methods in adaptive lenses, some form or another is used in virtually every form of compact, near-eye display. Adaptive lenses work similarly to prescription glasses, redirecting the eye’s focus to resolve issues in VAC and focal rivalry.
Solutions in Development
In addition to these already available solutions, other options are in the works.
Adaptive lenses are already in use but there are still many advances to be made. Previously mentioned XR technology company Adlens is working on developments in adaptive lenses. For example, the company is developing its stimulated eye engagement ( SEE ) technology which addresses VAC. They are also designing lens systems that use dynamic focal integration ( DFI ), which will address the focal rivalry problem.
Still in development, light field displays aim to render images affected by light from multiple angles. This more realistic model would reduce focal rivalry. However, it requires currently impractical computational power.
Another potential solution involves liquid crystal lenses, similar to those used in modern televisions. The display could potentially replicate changing eye focus. This technology is still in development by XR technology giant Oculus and its parent company Facebook Reality Labs. It too comes with drawbacks. For one, a reduced field of vision. Further, because the display cannot let light through, it could not be used for AR unless with some advanced VPS technology.
Development and Future Growth
So, what is all of this innovation worth? Quite a lot. According to the report, “widespread resolution of VAC and focal rivalry could result in nearly $10B in additional market value by 2026.”
While the authors write that most of this growth will initially be in industrial markets, more casual users have much to look forward to. Industry market growth drives hardware and software developments that are likely to pass down to other sectors. Further, these developments are likely to become more affordable and accessible for the rest of us as the industry adopts them.