The present invention provides an improved
light guide with inherently more flexibility for display
system designers and higher
optical efficiency. By using a
light guide containing substantially aligned non-spherical particles, more efficient control of the
light scattering can be achieved. One or more regions containing ellipsoidal particles may be used and the particle sizes may vary between 2 and 100 microns in the smaller dimension. The
light scattering regions may be substantially orthogonal in their axis of alignment. Alternatively, one or more asymmetrically scattering films can be used in combination with a backlight
light guide and a reflector to produce an efficient backlight
system. The light guides may be manufactured by
embossing,
stamping, or
compression molding a light guide in a suitable light guide material containing asymmetric particles substantially aligned in one direction. The
light scattering light guide or non-scattering light guide may be used with one or more light sources, collimating films or symmetric or asymmetric scattering films to produce an efficient backlight that can be combined with a
liquid crystal display or other transmissive display. By maintaining more control over the scattering, the efficiency of the recycling of light by using reflective polarizers can also be increased.