Head Mounted Monocular Display Systems...
The monocular display allows for the user to view information brought forth on his/her computer display, while at the same time allowing for uncumbered viewing of their surroundings. Click Here for an example.

Monocular display systems have certain criteria that must be met. They include:
- Low overall weight - if the display is heavy, it will be very uncomfortable for long periods of time, as well as restrict the movements of the user, since a higher weight will induce inertia into the display. possibly causing the display to from the head just from a quick head movement.

- Low Power - Low power consumption is a must, since at the moment all wearable computers are battery powered, and have no practical means of recharging while "on the go".

- High Resolution - What is the purpose of wearing a computer if you cannot read the information displayed? High resolution..ie quarter VGA and higher, is paramount to the usefullness of wearable computers.

This diagram represents the "sweet spot" in which a monocular display is worn, but the user still has full view of his/her surroundings.

image courtesy of Liquid Image