# Basic understanding of collimating near eye display

#### nikosb

Hi,

I am a mechanical engineer with very basic knowledge of optics. I am working on a project where there is an image at some distance below the eye, approximately 150mm, and I would like to reflect that image as far as possible using a mirror so they eye doesn't have to focus close. Here is an illustration of the system:

The image source measures about 1x1in, and it is located approximately 150mm away from the eye. I ordered a 90 degrees off axis parabolic mirror from Edmund Optics with a EFL of 152.4mm. When I tried to reflect the image as is shown above the virtual image was still very close to the eye, probably at distance of approximately 300mm. I tried increasing the distance between the image and the mirror but the reflection becomes blurry very fast. I thought that if one places an image at the focal point of a concave mirror then the virtual image would be at infinity. What is wrong with the above setup and how could I reflect the image at a large distance (1 or 2m)?