Mosaic3
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Version 3.5 rev 8 May 2019
PRODUCT OVERVIEW
2.3 o
vervieW
of
dmd a
rray
t
echnoLogy
The core of Mosaic is the Digital Micro Mirror Device (DMD), a high speed and highly efficient semiconductor-based
“light switch” array (800 x 600), of hinge-mounted, addressable, tiltable, microscopic mirrors. When a DMD chip is co-
ordinated with a digital video or graphic signal, a light source, and beam delivery optics, its mirrors reflect a digital image
of the illumination mask onto the sample. The pixel mirrors of the DMD are an array of squares that tilt at the corners as
illustrated below:
Figure 4: A representation of a small area of a DMD Mirror array (face-on view)
ON Mirror (+10 °)
OFF Mirror (-10 °)
Tilt Axis
Incident light (90 ° to Tilt axis)
Reflected light from
ON
Mirror coming out of page
Reflected light from
OFF
Mirror going to the right
In the DMD power-off state the mirrors lie flat at 0° to the beam direction. When any mirror is switched ON, the tilt angle
is +10° to this flat state, and -10° in the OFF (powered-on) state. DMD pixels are tilted to either the ON or OFF state, and
held in place by electrostatic attraction. The light from the standard illumination source is shone at 90° to the tilt axes of
the DMD (as shown above) and 20° to the “flat normal”.
Figure 5: Cross-sectional View of a DMD Mirror
By controlling which mirrors are in the ON state the user can control which areas of the sample are illuminated at the
microscope.
