Various embodiments involving structures and methods for illumination can
be employed, for example, in projectors, head-mounted displays,
helmet-mounted displays, heads-up displays, back projection TVs, flat
panel displays as well as other optical systems. Certain embodiments may
include prism elements for illuminating, for example, a spatial light
modulator. Light may be coupled to the prism in some cases using fiber
optics or lightpipes. The optical system may also include a diffuser
having scatter features arranged to scatter light appropriately to
produce a desired luminance profile. Ellipsoid- and parapoloid-shaped
combiners may be employed in embodiments of displays such as for example
head mounted displays, helmet mounted displays, and heads-up display.
Other embodiments are possible as well.