LATEST STORIES DARPA realizes it needs contact lenses, opts for those nice AR tinted ones (video)

BY SHARIF SAKR POSTED APR 13TH 2012 05:31AM

DARPA saw the battlefield potential in AR glasses ages ago, when even Sergey Brin was happy to wear regular Ray-Bans. It's now stepped up its investment, giving more cash to one of its research contractors -- a company called Innovega -- to produce prototype contact lenses that could make military wearable HUDs smaller and less conspicuous. Innovega's iOptik lenses don't actually include a display, but rather allow the human eye to focus on an image from a separate accessory that sits right up close to the eyeball. The lenses have different zones that give the wearer multiple areas of focus, so they can see the overlaid augmented reality HUD -- such as a feed from an overhead drone -- but also warlike events going on in the immediate environment. Judging from the video after the break, however, calling them plain 'bifocals' might be taboo.

http://www.engadget.com/2012/04/13/darp ... ct-lenses/

The Darpa ones are interesting. It looks to me like they are working on a kind of dual focal distance lens, which is something I hadn't even considered. So it's like a lens inside a lens. The middle lens would be focused on the extreme closeup, and the outside would be just regular focus. My main concern with this is having to put in the contacts... one of my least favorite things to do. Remember too that these are likely to need to be solid lenses which are renowned for causing discomfort.

I know we discussed contact lenses for a head mounted display on one of these forums. However, the bifocal topic is new.

With contact lenses there are few different approaches to bifocals. All off them are soft ones, as far as I know. One is a bit larger than a normal contact lens, but not totally round. The lower portion is flattened, so it tends to rest on the lower eye lid. When you look down, your lower eyelid pushes against the contact lens, so that you are no longer looking through the center of the contact. The lower portion of the contact lens having the reading distance prescription.

The other technology, which I am less aware of, has the eye always seeing through both focal lengths. Essentially creating a double image. But, one of the images is out of focus, so it is supposed to be viable for the wearer to concentrate on the in-focus image. However, this obvious has a certain amount of image quality reduction.

I just did an internet search and came across this great article on the various multi-focal contact lenses, http://www.allaboutvision.com/contacts/bifocals.htm .

I can also see other technological possibilities. A holographic optical element, similar to that used by the manufacturers of transparent rear-screen projection surfaces may be viable. Such a lens would accept the light from a projector coming a specific direction, while still being transparent to light from outside. I imagine the holographic lens can also have a different focal length from the rest of the lens.

Now that I think about holographic optical elements, I imagine it might just be possible to adapt the same idea to non-contact optics for a HMD. One of the challenges with optics in a HMD is that as your eye moves around, you move out of the focus point for a standard lens. A holographic lens might just be able to adapt to that by presenting the eye with what amounts a different lens as it moves around. As I think even more about it, I was reminded that holographic images are specific to certain wavelengths. But, rather than being a liability, it would allow the creator to adjust for chromatic aberrations. In other words, create one holographic lens for red, another for green, and a 3rd for blue, and put them on a multi-channel hologram.

Joe Dunfee

what I thought as an option for the multi focal points lens is that it could use polarization on the part of the lens that is used for the extreme close focus and on the outside of glasses (kind of like the concentric lens design), so that you only get the light from the glasses reaching the retina. So you have a lens in the middle of a lens. The outside would be for normal focus and not have any polarizing, the inside would have an extreme lens with clockwise circular polarization. The glasses would have a coating on the outside with counter clockwise circular polarization film.

With the non-stop ideas, it looks like DARPA needs to look here for their R&D staffing.

Joe Dunfee