Rayneo 3 Prescription Lens Hack

 

I've been using a head mounted display for a number of years and find it useful on occasion. The unit I have is Kickstarter project that never went anywhere. It's about dead and could kick off at any time.

After some internet research, I settled on the Rayneo 3S Pro. I ordered one on Amazon and it seemed pretty good when I tried it. Problem though. I have prescription lenses and need them for distance. Unlike my previous set, the Rayneo has no option to adjust the diopter to adjust for the user's prescription eyewear.

The Rayneo has an option to buy a set of prescription lenses that snap into the Rayneo 3S unit nicely. But they're over $100 and have to be ordered from the UK. Figure weeks or months at least, plus I'd be out $100.

Rayneo Demo Lens Mounting Point

Luckily, the Rayneo 3S comes with a "demo" frame set with the all important mount that snaps into the frame oh, so nicely. I took one look at that and knew I could do something with it besides dream.

I rummaged through my old glasses drawer and found a recent pair with few scratches. The important consideration is the lenses from the donor glasses have to be bigger than the lenses in the demo frame. Hardly difficult as they are tiny lenses for the Rayneo.

The lens is mounted to the demo frame with two metal posts and secured with a plastic cap. There's no way I could drill those tiny holes accurately. 

The frame itself mounts to the Rayneo 3S using a tiny and very difficult to deal with clip. It's a tight squeeze between the nose piece and the optical elements. 

I considered several possibilities for mounting my lenses to the Rayneo frame. I thought about grinding both the lens and the mount at an angle so they could meet up perfectly and be in the same exact plane as the demo frame lenses. I ruled that out as it would require too much precision. I only get one shot (one set of demo lenses) so it seemed that it had to be a less technical and more forgiving process if I was going to be successful.

Scrap wood and clay jig

I settled on grinding the demo lens down to a nub and thinning it out by about half. Then superglue my lenses to the demo lens frame in a jig. That seemed pretty doable.

For a jig, I started with a piece of scrap wood, traced the demo lens outline onto it, and built up a block of clay on each side. I weighed the clay blocks first to start with exactly the same amount of clay on each side. The point was to build up two nearly identical pillars to hold the lenses in place.

To hold the demo frame in place, I ground down a piece of scrap aluminum into the shape of the attach point. The purpose is to insure the demo frame is centered when it's glued to my lenses. 

My donor frames protected with tape.

Before I did anything with my lenses, I covered both front and back of the lenses with tape, the kind that can be written on. It's way too easy to add scratches.

It helps removal to overlap the tape.

To trace the outline for the lenses onto my lenses, I first coated the demo lenses with a glob of clay so they would stick to the lenses and make it easy to trace the outline. This worked remarkably well. I could spend effort centering the demo lenses before I did the tracing. I traced on the front, then I copied the outline on the back for good measure.

Demo lenses in place

After removing my lenses from the frames, I cut them to size using a disk sander. It took about ten minutes. The lenses give in easy to the sander. I have a 12" disk sander with 80 grit paper. A Dremel would work great for this too.

A note about pupillary distance (PD)  and orientation. It might seem like I'm going through a lot of trouble to position the lenses. I do this because my lenses are cut for a particular PD. If I don't keep the lenses the same distance apart, then that PD will change and the center of the lens won't be at the center of my eye. This will cause distortion in the image and ruin the display.

Donor lenses cut to shape.

The other important consideration is orientation, or in optometrist terms, astigmatism. Prescription lenses may have a correction for astigmatism that is based on the orientation of the lens. If the orientation of the lens changes from the way the manufacturer oriented the lens, then the astigmatism correction will be alerted too. For me, this results in a smeared or squished image.

I cut the demo lenses down to size and thinned them out to about half the thickness, plus ground off the plastic cap holding the lens to the frame. Naturally, the lens fragment came off at that point. To reattach, I used a drop of super glue. That seemed to do the trick.

Demo frame carved down to the right size.

One thing that made this a difficult process is the size of the demo frame. It is tiny and easily dropped or bobbled. If you attempt this process yourself, do everything slowly. This is not a job you want to rush through.

Unfortunately, I didn't take a picture of the demo frame in the jig. To mount the frame in the jig, I just pressed it into the clay so it looked square and straight, double checked by measuring the height of the two lens mounting points and they equal.

Attaching my lenses to the demo frames was a bit anticlimactic. I put a drop of super glue on the lens and placed it carefully in the jig. The clay acted like temporary glue to hold the lens at the right angle and orientation. That worked well.

After a few minutes, the glue had set and I popped the set out of the jig. After cleaning, this is what it looked like. The spots on the lenses where the frame attached to are out of view. 

Mounting the demo frame in the Rayneo 3S Pro was a lot more difficult than it should have been. It's a very small clip and difficult to see. Once it went in, it was in, and the clip held.

I tested them out and the picture is crisp and completely in focus. I can see edge to edge with correction. I see zero issues with this installation. I declare this a successful hack.

Cost: Zero.

Time: About two hours, not counting waiting time for the glue to set.

Difficulty: I'd rate this a 2.5/5 due to the tiny parts and the one chance at getting it right. I doubt Rayneo sells just the demo lens.