Moved to the Area 51 Display Resesearch, Science & Engineering
You only need 320x240?
The chinese bazaars are a wonderful hobbyist parts supply for building DIY headsets at home.
They may not be as good as the best stuff but even the original Oculus Rift prototype was essentially built in an RV trailer before the KickStarter. It was literally a garage DIY success story, cobbled together from parts like these! But sometimes you gotta make-do with what's supplied; it was the commandeering of small tablet/smartphone/DVD player displays in existing supply to do something it was never intended to do: virtual reality. It wasn't as good quality as today's Oculus but it was 1000x better and cheaper than previous VR.
You have to be creative sometimes, whether for VR or AR
-- For example, 3D printing a custom case that makes them less fragile, then adding felt pad/foam to fit properly over eyes.
-- Use overkill resolution and simply use GPU scaling to scale down to 320x240. Etc.
-- Modifying an off-the-shelf plastic Google Cardboard headset to turn it into a headset
I have anecdotally heard that hobbyists can tinker with digital camera viewfinder displays instead, or jerry-rig parts normally targetted to video goggles (those cheap 640x480 headsets), such as these 640x480 ones
or such, though custom modifications are often needed to make each eye display some different graphics, etc.
Tech obscolence can throw obstacles to goals. I do not think you will succeed in finding 320x240 microdisplays, they almost no longer make them cheaply at less than 640x480 -- it's like paying $30
to get old 32 megabyte (0.032 gigabyte) EDO DRAM sticks when 4096 megabytes (4 GB) DDR4 cost only $28
. Holy price differential, Batman! The low-resolution technology, in some cases, is starting to (A) get low quality like 20-year old ghosty LCDs... or (B) get expensive and harder to find so you may have to make do with overkill resolution and downscale.
For example, the hobbyist exercise is to find the cheap supply of off-the-shelf resolutions in all tech (DLP, OLED, LCD, etc), sizes, and requirements, and go with the best-fitting-spec to your "Maker Movement Skillz". Grab the cheapest moderate-resolution, and then MacGyver from there, including scaling as needed, whether via the built-in chips, or via your mobile GPU. Even all modern smartphone chips (ARM+GPU combos) include high quality scalers nowadays, so it's no effort to scale 320x240 to any target resolution (either pixelly scaling or blended/filtered scaling) and does the job quicker and cheaper.
Garage-lab creativity is currently required to do what a hobbyist needs to do to cobble together a homebrew DIY display solution that fits your goals.
Note: I have experience with Blur Busters Services
as well as homebrew hobbyist display hacking (Blur Busters was born because of a homebrew scanning backlight project), hope this post helps you get down the right direction!