A MEMS device such as a grating light valve light modulator is athermalized
such that the force required to deflect the movable portion of the MEMS device
remains constant over a range of temperatures. In MEMS embodiments directed to
a grating light valve light modulator, a ribbon is suspended over a substrate,
and the ribbon tension is kept constant over a temperature range by adjusting the
aggregate thermal coefficient of expansion of the ribbon to match the aggregate
thermal coefficient of expansion of the substrate. Various opposition materials
have an opposite thermal coefficient of expansion as the aluminum layer of a grating
light valve light modulator ribbon, using the thermal coefficient of expansion
of the substrate as a zero coefficient reference. The adjustment of the thermal
coefficient of expansion of the ribbon can be performed variously by thickening
existing layers of opposition material or adding additional layers of new opposition
material to the ribbon, or reducing the aluminum in aluminum layer. The aluminum
layer may be reduced variously by reducing the thickness of the aluminum layer,
or reducing the surface area that the aluminum covers, or reducing both the surface
area and the thickness. Embodiments may combine the reduction of aluminum with
the use of opposition materials.
