US Patent 7450310 Head mounted display devices

One embodiment of the invention comprises a simplified light-weight head mounted displays comprising an off-axis combiner and a pair of plastic lenses. One of the lenses is a rotationally symmetric optical element and one of the lens is a non-rotationally symmetric optical element. This non-rotationally symmetric optical element comprises first and second lens surfaces that are tilted and decentered with respect to each other. One of these first and second lens surfaces may also include diffractive feature to provide a diffractive or holographic optical element for color correction.