A display apparatus includes a spatial light modulator, such as a digital
micromirror device or an LCD panel, and a lighting unit that illuminates
the spatial light modulator. The lighting unit may include red, green,
and blue lamps which emit light that impinges on a DMD from at least two
different directions. The lamps may be flash tubes which are fired at
different binary levels in accordance with the rank of the bits that are
being displayed on the DMD. The lamps may be fluorescent lamps which are
driven steadily at predetermined levels while the rows of micromirrors
are turned on in sequence and subsequently turned off in sequence.
Resetting to dislodge micromirrors that have become stuck can be
accomplished by emitting current pulses through the micromirrors while
exposing them to a magnetic field. The illumination unit may include a
lamp unit and a color wheel. The light from the lamp unit can be
integrated, and the data displayed on the spatial light modulator can be
changed when the integrated light reaches a predetermined value. The
color wheel may be rotated faster than the frame repetition rate of video
information that is being displayed. The intensity of the light may be
controlled in accordance with the bit rank or significance of the bits
that are being displayed by the spatial light modulator. Several
techniques for achieving different intensity levels are disclosed.