Knowing the long-term average landed duty cycle (of the end product or application) is important because subjecting all (or a portion) of the DMD’s micromirror array (also called the active array) to an asymmetric landed duty cycle for a prolonged period of time can reduce the DMD’s usable life.

The symmetry of the landed duty cycle is determined by how close the On-state and Off-state percentages are to being equal. For example, a landed duty cycle of 50/50 is perfectly symmetrical whereas a landed duty cycle of 100/0 or 0/100 is perfectly asymmetrical.

For extended useful lifetime of the DMD, it is strongly recommended not to put any individual pixel in a 100/0 or 0/100 duty cycle for prolonged periods of time. It’s recommended as much as possible to put the DMD in a 50/50 duty cycle across the entire DMD mirror array, where all the mirrors are continuously flipped between the on and off states. A few examples when the DMD could be in a 50/50 duty cycle mode include: when the system is idle, the illumination is disabled, between sequential pattern exposures, or when the exposure pattern sequence is stopped for any reason.