Easy "Pancake Lenses"

Because paying $2k for a piece of plastic is BS. IPD system included.

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License: CERN Open Hardware Licence Version 2 - Strongly Reciprocal,
also you can use it in a patent but you can't make it as a patent or try to sue others who use a similar system!

While working on the Vector Gear, my upcoming headset (shameless plug), I wanted to use Pancake Lenses. However, all the solutions for it are either not on the market or very expensive. So I decided to open up a phone VR and study it. While doing so and rearranging the optics, I found that setting the lens in a certain way allows it to make clear images when not far from the screen. This allows the display to be extremely compact, while not sacrificing the FOV. This was made to share my findings and find ways to make the lens even less distanced.

Overall, this method turns the distance from the optical lens to the eye much closer than it would otherwise be. To help show this, I used my computer camera (which isn't a super close representation due to the wider FOV and the focusing being slightly off, but is still very close to the distances I deal with when using the display).

To begin, I used the standard checkboard image. This allows me to most clearly check for warping, chromatic abbreviation, etc. The image is below for anyone who wishes to do the same, although perhaps you could use an image with more grids.

Checkerboard Images – Browse 65,982 Stock Photos, Vectors ... 

To see the difference between the current optical unit and the standard, I used the camera to take a picture of how the image looks within the lens, and the distance from the camera to the screen (albeit not to perfect scale of course, not until I print a system for this). Also do be aware that the camera has a low resolution, in reality the brightness of the image seems to almost be completely kept and the images are sharp when you find the perfect depth.

Standard lens view (wider due to angle):

Distance (I'll try to make these better next time, the screen and BG is shown to get a better idea of distance)



Even though the image is not perfect, it's easy to tell that there is a huge difference in distance. In fact, I have reason to believe that changing the lens focus and distance from each other can greatly affect the distance to be reduced even further. I have a prototype of the Vector Gear which uses pancake lenses, and the distances are not greatly off from each other. I believe that further experimentation will help greatly.

However, this does not come without problems. 

As a wise man once said, when God opens a door, he closes a window

In this case, the following occurs:

- Chromatic Abbreviation (Not extreme but noticeable, can be solved with software)

- Made for smaller displays (You would need a larger lens and a more dense lens to have a better image, I can see the pixels on my phone for example, however could be fixed by scaling)

- Wider FOV for smaller area (less of the entire image is shown, which can be seen as both a good and bad thing. It allows the illusion of a much larger display, but you also have to account for the fact that you're working with less screen. A potential fix is again, scaling)

- Warping (Which can be solved with software)

All tests done, including the expansion of the headset's FOV will be recorded and shared for anyone to replicate (Because I HATE gatekeeping), I believe this is well worth the time and effort as it gives what some vendors attempt to sell at a $2k priceline (literal, hello Kopin P95) at what is likely $8 a piece at the very max. I also will be designing the IPD and depth systems to use within the headset, with an electrical based interface (servos and motors instead of regular mechanical).


PsuedoPancakev2b, fixed lens to display distance

obj - 120.27 kB - 10/27/2023 at 14:41


Boson Print.obj

Main v2 print file with IPD system, lens holder, etc, small fix needed for display to eye distance (literal penny thickness addition needed)

obj - 453.83 kB - 10/26/2023 at 22:32



A file showing the parts generally together

x-zip-compressed - 129.12 kB - 10/26/2023 at 22:32


PsuedoPancakes v2.svg

The lens you want to cut, remember use 2 60mm and 2 70mm! Also ensure you flip one 60mm and 70mm so all have the smooth end facing the user's eye

svg+xml - 2.74 kB - 10/26/2023 at 22:32



Version one of the lens holder (check for errors!)

Standard Tesselated Geometry - 68.25 kB - 04/19/2023 at 00:15


View all 7 files

  • Project Log 8: BASE OPEN SOURCED

    WalkerDev10/26/2023 at 22:32 0 comments


    An 8th log was made but I have no clue why it didn't upload!

    I am open sourcing the base headpiece right now, meaning you can build around it and make your own dream headset! This is the bases needed for an IPD system, faceplate and lens! I need to make fixes though, such as a better coupler design, actual screws and making the design more smooth (which i've done but haven't shared)

    For the rods, the top should be an aluminum rod and the bottom a threaded rod! Links below:

    Top Rod:

    Bottom Rod (Buy Two)

    As for the lens, here is where I have mines cut from! If you ask for the Pancake v2, they will know which ones you mean! 

    Lens (Buy Two 60mm and Two 70mm)

    Display (Hopefully I can share the 90hz ones soon!):

    Remember to have the lens smooth side facing the eye and put a 60mm and 70mm on each side! Order doesn't matter!

    Finally for those without a printer, feel free to use this PCBWay! You can also donate to me and help me work on this and other tech for a living or download the model here as well (soon)!

    This is under the Hackaday page as Boson Skeleton (Assembly Reference), Boson Print (Easy Printing) and PsuedoPancakes v2! I have to make some tiny changes (making the wall thicker for the display, although for my use a bendy one helped) and 

     Do keep in mind the LCD piece needs a small fix (the screen should be a little further back) and that this was a rough model made with Tinkercad!

    Final note, the lens design might look empty but it's using a 0.001m line thickness! If you use an editor and change the stroke value, you will see it!

    General Assembly

  • Project Log 7: IPDs, Lenses and Sponsorships

    WalkerDev09/07/2023 at 23:04 0 comments

    So I FINALLY have an update on the progress of things over at my side! While there is a bit of bad news, there is a lot of good!

    Let's get over the bad aspects. Sadly, I was not able to get the PsuedoPancakes v2 to test because the company I brought from temporarily shut down. No problem, I already had a replacement ready! The only difference is it will take longer since I have to buy them again. Now that that's out of the way, let's get to the good.

    First off, SPONSORSHIP!!! PCBWay has helped me by allowing me to test out my 3D models with higher quality materials and processes. Before we continue, it's important to know that there is a new project coming soon; an open source VR headset for $270! There are permutations of this headset as well which can do even PCVR in a standalone fashion but that's for later! 

    The headset design below was made by me! Now being honest, this needs a LOT of cleaning, but more on that for later! For now happy thoughts.

    Being serious, there are a few things to keep in mind when looking at this:

    • This uses dual 2160x2160 displays
    • The eye module uses the psuedopancake design, keeping the lens and display the perfect distance away to work. In another revision I might make something for focal distance but this is honestly unlikely
    • The outside of the headset would use a padded piece to both act as a shadowbox and comfort
    • There is a simple IPD system in there designed based off of the Valve Index, using two threaded rods at opposing directions to the bottom and a third smooth one at the top. The top acts as a guide whereas the ones to the bottom ensure the display will move the lens without the rod actually going in or out.
    • The front layer was the most unknown aspect, given I had much hardware to put within.
    • There is a headstrap and headphones as well, edited. 
    • Headstrap:
    • Headphones:
    • The eye module looks like it would go into the nose but because of proportions and the nose curve it doesn't.

    Now to get it working, I went to PCBWay and uploaded my model! From there, I spoke to an engineer who helped me by notifying me of errors in the model and some small fixes I could take structurally. Be sure to know how many parts you want to have printed! I was also able to work on my puck model too.

    Now, the parts arrives and PCBWay did a great job! There are blemishes and the like but those are from me messing up with an adhesive lol.  Let's take a look at what has been done with the IPD and eye module system before dealing with the rest!

    As you can see, the eye module requires pretty simple setting up! I am going to increase the thickness of the material the plate is on and make two snapped together so you can easily replace screens instead of permanently putting it there! I didn't realize it while modeling but it turns out the first board for the system fits nicely! I will likely add a smaller extra part for wires to go through for cameras, peripheral LED, etc.

    The IPD system still needs some work but it functions! I ended up making the holes too small for the top and realized it's best to use threads which can be set for the lower area! Thankfully made a 3D model of the estimated size so I could put in without effort! It looks like it works without needing a fancy gear system so this will be my default! 

    Overall, I am going to make changes to these systems and ensure the v2 works before I put the files here!

    First up is the headset! Let's take a good look at how the system looks 

    *My favorite shot, I will overuse it in the future

    *Headset from the side

    *A closer look at

    *The puck, housing a Ryzen system. More work to do here! Someone said it was like a little Gman suit

    *Where the psuedopancake should be and the display, with the increased focal distance it should be all good

    *Found out I can hold this together and make it a singular part of the eye module instead of needing to take...

    Read more »

  • Log 6: Upgrading The Lens Design and Making More Of A Real Headset

    WalkerDev08/06/2023 at 17:31 0 comments

    A few small upgrades have happened from the last update to now! For example, let's start off by looking at the new lens design!

    Some pros of this design includes

    • Cuts off part of the vertical FOV but only at an area which makes not much of a real difference
    • Upper inner side fits eye peripherals better, meaning even better inner FOV view
    • Lower nose area now accounted for, covers 52mm to 72mm IPD
    • Outer side and lower side still same for higher FOV

    Also it will have about all of the 2.9 inch display visible without the borders, but still will 120mm focal length lens! As a reference, I made a scale drawing of the lens and put the original design atop it! I then shaded the part which was removed in black! 

    When we put a lens over, let's see how much of the black is visible!

    As you can see, the area in black is not visible mainly due to the fact that the area can't usually be seen by the user anyways! Going to test as the design is coming, as soon as it's done and it works, i'll share the design here! I also am heavily considering putting it on Tindie and/or Alibaba as my own store, given how well these work!

    Aside from that, more sneak peek of the headset! This will be under it's own project given the extent I will go with this, but I will also open source it and possibly put it on TIndie!

  • Log 5: 3D Models and Enclosures

    WalkerDev07/25/2023 at 03:08 0 comments

    Soooo, I was supposed to send this yesterday but am holding back since I want to check the lens within a full model first!

    As you can see, I designed a simple enclosure for testing the lens! This version will hold two 2.9 inch LCDs, the drivers for it, an IMU and Arduino! I might also add in a Raxda for some simple PCVR experience with 6DOF!

    From this, I am going to make a test headset and open source it (probably under a new project) and go onto an AR headset version!

    In particular, I know I have to switch the 70mm focal length lens with 100 - 120mm to cover the entire image! I also am going to change the lens design to have an IPD system!

    With this, I will print the headset parts down to the knob adjustment system as a way to see what changes might need to happen!

  • Log 4: Housing Test :3333

    WalkerDev07/23/2023 at 01:26 0 comments

    Finally more work on my headset, particularly the pancake lenses are almost done! 

    I am going to increase the focal distance on the front lens so the display edges can't be seen. Tried and it worked with 3 lenses but because of 3, image quality dropped. I am aiming for 100 to 120mm to work hopefully, else I will just reduce the size of the lenses. 

    I also am considering not adding an IPD system because the sweet spot is HUGE, if I did I also would make a small edit to the lens, allowing IPD from around 47 to 75mm. Dimensions so far are 6 x 0.75 x 3 0.75 inches, with the motherboard and eye tracking it will likely only change in depth to 2.5 inches. 

    Tomorrow I will add in the display, peripheral LEDs and the part to cover the eye section. That part will snap on since in final it will be connected to padding, for easy cleaning. Then I can add in the x86 mobo, eye tracking and an IMU before moving to the cameras and finally the headstrap. I will open source those parts too, albeit later since the complete headset is actually for a product! I will however be dropping the models here with a few notes tomorrow with a few notes in an update!

  • Log 3: IPD Systems, Displays and XR

    WalkerDev06/22/2023 at 19:47 0 comments

    Hey, some notes on progress!


    This is a scale show against another optical module! Mines is larger for a better FOV, while also being designed in a way where you can view a full image with the nose in mind (which a circle design does not account for)!

    I tried to take some photos with the lens but was using a phone so the images came out distorted! I will show two anyways.

    I used a 2.9 inch 2160x2160 display instead of my phone, although the lens can easily be scaled for other headsets! Soon, I will make a tutorial showing exactly how to do this!

    It's a bit hard to tell through these, but there are no RGB lines (which seemed to happen because of phone), god rays are almost nonexistent and the display is a small distance away from the lens, at 0.75 inches! With the lens system being around 0375 inches, this puts the entire system at around 1.2 inches! This matches the Kopin P95 pancakes, which boasts 2.6kx2.6k at a 1.3 inch form factor, however mines having a wider FOV, being more ergonomic and literally costing %1 the cost. 

    More updates to come, working on a next gen lens system to make the FOV as wide as possible!

    I will drop the model once I have the next part working!

    More on this soon.

  • Lens Cut + Files (THE LENS ARRIVED ^^ )

    WalkerDev04/19/2023 at 00:07 0 comments

    The cut design has finally arrived and I have managed to test it with great success!

    Overall, the lens are a success! The FOV vertically is wide to the point where I have to strain my eye to see the top and bottom of the lens! I am working on extending the horizontal FOV as it is comparable to the Quest 2, but WE MUST GO BETTER! In the next cut, I will make the lens bigger!

    Currently, the images are extremely clear and do not require an extremely bright screen! However, there is an obvious chromatic abbreviation and some God Rays, which I can fix with a hot mirror! The entire lens is clear and there is no sweet spot, as the entire lens is completely clear instead of there being a blur effect from what i've seen! It is a little hard to see very small text, but that is probably because i'm testing VIA my phone, where I can see the pixels in some images! Warping also is not very present! 

    I am not sure about the chromatic abbreviation since I used my phone and the proper VR display before, and while the chromatic abbreviation and godrays were present in the phone test, it was not in the display test!

    I use two lens here, a 60mm and 70mm focal length design, both lens being cut from a 70mm diameter! I used the following:

    If you ask them to cut WalkerDev's design, they will know to cut the v1 for now!

    This costed me around $16 to make enough for a headset! That currently is 0.8 percent of the cost I was given when I requested a pancake lens originally! have 4 pairs but have kept the others closed while I work on a cardboard design to test it!

     In the files section of the project, i've attached both an STL and DWG of it for use! You have to play with the distance as i've yet to design the other systems like an IPD adjuster! I also attached a model of a model for a lens holder!

    Feel free to make it, share what you find and more in the Discord Server here!

    In the next update I will upgrade the horizontal FOV and possibly attempt to add a hot mirror to help with the chromatic abbreviation problem! Or maybe test the lens on a proper display and check if the chromatic abbreviation exists then!

    Please adhere to the license guidelines at the bio!

    (I will put the measurements of spacing for the eyes to lens later within the week)

  • Lens Design Completed

    WalkerDev03/03/2023 at 17:00 0 comments

    Small update, the CAD design was completed for the lens and i'm currently waiting for it to be cut, the lens company agreed to send an image of the lens when they are cut! At the time i'm waiting to test out the lens and make the enclosure for it before I share the file completely! However, here is the current 3D representation of the lens, as well as the drawing!

    The lens is designed to give a 40-45 minimum IPD, while having the largest possible FOV! If you look to the left or right, you will see the majority of the screen regardless of your IPD, with the FOV not sacrificing FOV! The lens are made for a 70mm and 60mm lens (given I am remembering correct lol) and will include a LED based diffusion at the peripheral to artificially increase the FOV even further!

    The current cost for the lens should be $20 - $25 so far!

    3D Representation:


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