(1) For some applications, it is critical to account for the micromirror tilt angle variation in the overall optical system design. With some optical system designs, the micromirror tilt angle variation within a device may result in perceivable non-uniformities in the light field reflected from the micromirror array. With some optical system designs, the micromirror tilt angle variation between devices may result in colorimetry variations, system efficiency variations, or system contrast variations.

(2) DMD efficiency is measured photopically under the following conditions: 24° illumination angle, F/2.4 illumination and collection apertures, uniform source spectrum (halogen), uniform pupil illumination, the optical system is telecentric at the DMD, and the efficiency numbers are measured with 100% electronic mirror duty cycle and do not include system optical efficiency or overfill loss. Note that this number is measured under conditions described above and deviations from these specified conditions could result in a different efficiency value in a different optical system. The factors that can influence the DMD efficiency related to system application include: light source spectral distribution and diffraction efficiency at those wavelengths (especially with discrete light sources such as LEDs or lasers), and illumination and collection apertures (F/#) and diffraction efficiency. The interaction of these system factors as well as the DMD efficiency factors that are not system dependent are described in detail in DMD Optical Efficiency for Visible Wavelengths.