
Unexpected behavior with a Fresnel lens and concave mirror.
I have a setup with a micro oled display, that goes through a beamsplitter then reflects back up from a concave mirror that diverges/magnifies the image and then back through the beamsplitter to the eye. I added the Fresnel lens shown in the image above with its top face being placed exactly at 3mm from the micro oled display. The image produced that goes to the eye; I can see the colors of the display, but I mostly just see the grooves of the Fresnel lens. I have verified orientation and focal length distance. I have also tried to increase and decrease the distance between the lens and the display. Are these lenses just not suited for small displays or high resolution imaging?