See-through computer display systems

A compact head-worn display with multiply folded optics providing displayed images overlaid onto a see-through view of a surrounding environment comprising:

• a. A solid prism of a first material with an angled planar surface to fold an optical axis and one or more surfaces that provide optical power;
• b. One or more additional lens elements with optical power made of a second material that is different from the material of the solid prism;
• c. An image source that provides image light associated with the displayed images;
• d. A combiner that folds the optical axis and directs the image light toward a user's eye;
• and
• e. Wherein the multiply folded optics provide a more compact head-worn display and the first and second materials are selected to reduce a lateral color in the displayed images.