MEMS Display Controller
RPM Associates Technical Consulting

Imagine a display where every pixel is a simple shutter, either allowing light through, or not. It’s effectively a binary display — the shutters only have states of 0 or 1. How can you present a movie on such a display? How do you make colored dots on the screen?

This is an area in which we have a lot of expertise, going back to designing some of the first displays of this type in the 1990s. Back then the technology was Liquid Crystal on Silicon (LCOS), where a small chip is covered with liquid crystal, and the electrical signals from the chip change the optical properties of the liquid crystal. Cool stuff.

At the time, Texas Instruments was also developing their DMD technology, which achieved similar results, but without any liquid crystal (and with about a billion more dollars!).  I still have a Samsung DMD projection TV in my family room, and I love it. Their chips are covered with millions of tiny mirrors that either reflect light, or not. Same principle, different implementation. This was probably the first MEMS (Micro Electro Mechanical System) display; since then several companies have introduced other MEMS technologies. One of these is Pixtronix, in the Boston area, which has since become a part of Qualcomm. Their technology consists of a backplane containing millions of tiny shutters as pixels; light from underneath is either passed through or blocked by the shutters. The shutters are activated (very quickly) by electrical signals ultimately related to the content of images to be displayed. This technology promises lower power consumption for mobile applications.

I can’t go into too many details of how one converts a video stream or images into the special signals that turn the shutters on and off, but suffice it to say that it’s not an easy problem, and entire new fields of investigation were opened up once light became binary. Some involved good things, some bad — like a whole new class of unwanted visual artifacts (color breakup, dynamic false contouring) that had to be minimized. We were involved in the very early stages of product development of this technology, contributing algorithms and then implementing them in FPGAs to drive the nascent displays. We eagerly await the amazing things Qualcomm will do with it.