There are many versions for face shield headbands. But all of them require making holes into the protective sheet by punching or laser cutting. Too complicated in my opinion. Here is my version of the headband without pikes for holes, making it truly minimalistic and still very functional. Use A4- or Letter-sized sheet as such or you can cut the sharp tip of the corners off. If you insert sheet horizontally, it will cover the sides of the face better.
Update 2020-04-14 V5: Removed V4 version, as its outer stripe slips over in some cases, so raised the height to 15mm. Slot for the sheet is a lot wider, so you can insert it horizontally to cover the sides of the face. 5pcs stack included.
Update 2020-04-12 V4: 10mm high version with hooks for buttonhole band.
Update 2020-04-06: Top cover added.
Update 2020-04-04: New V3 band allows putting wider sheets.
Warning! Do not print stacked version for medical purpose. Separated bands from the stack will have rough surfaces, that are not suitable for disinfection.
https://dima.fi/blog/designs/covid19-face-shield/
The author remixed this model.