Recent advances in the development of the Texas Instruments phase-only microelectromechanical systems (MEMS) spatial light modulator

Over the last few years, DLP® Products at Texas Instruments, Inc. has been developing a MEMS-based phase-only spatial light modulator that we call the Phase Light Modulator or PLM. The device which shares many of the process steps with the DLP micromirror device consists of a vertically actuated mirror on top of a CMOS array. The current reflective device provides enough vertical range to be suitable for visible wavelengths. This paper discusses a number of metrics important to the performance of a phase-only spatial light modulator and the corresponding characteristics of the PLM. The metrics include diffraction efficiency, number of phase levels, resolution, speed, and die flatness. The paper also discusses in depth recent design improvements such as increasing the number of phase levels to improve efficiency and reduce image noise. Recent lifetime test results collected over more than 1000 hours are also presented. Finally, there is a discussion of our possible approaches to testing the device in a high-volume production environment.