TDK was showing its latest Smart Glasses Equipped with a Full-color Laser Module during CEATEC 2023, and I had an opportunity to test it at their booth. The company has been working on this technology for several years, and things are moving along two axes.
First, it is possible to have a head-mounted display experience. Secondly, the same technology could be utilized in XR headsets. The technology relies on projecting an image directly onto the retina instead of onto a display surface the user is looking at.
This projection type does not require the user to focus on a nearby surface. The projected image is clear and sharp whether you look at something near or far, which would be an advantage for AR applications, where information would be presented in a heads-up display style. During the demo, some text was projected directly onto my retina (720p resolution), and it remained sharp as I looked at things close to me or far away. At this point, this is the most advantageous use of this technology.
Next, there was a VR-style demo, which TDK describes as the “World’s first VR goggles with direct retinal rendering.” Each eye has a projector, and of course, two images are rendered and projected on the retina. TDK developed this use case because classic VR headset that rely on a display force your eyes to focus on the close-by display to see a sharp image. This is causing some muscular-level eye strain, but simultaneously, the 3D image that is shown suggests an entirely different focus point. That could also cause cognitive strain.
In the direct-to-retina projection, the eyes don’t need to focus on a specific display surface, and the user is free to let the eye’s focus wander wherever the 3D image suggests, which would eliminate one source of VR sickness.
There are other theoretical ways to fix the eye-focus strain, such as using lightfields. However, that technique vastly increases the 3D-rendering load. TDK’s retina projection does not induce such an issue. However, retina projection requires a very precise projection and might be less forgiving when users move their eyes away from the projector.