Interferometric modulators are spatial light modulators typically used in display applications. These modulators use interference effects to control the intensity and the color of the light seen by a viewer. One example of such a modulator is the iMoD™. The iMoD employs a cavity having at least one movable or deflectable wall. As the wall, typically comprised at least partly of metal, moves towards a front surface of the cavity, interference occurs that affects the color of light viewed at the front surface. The front surface is typically the surface where the image seen by the viewer appears, as the iMoD is a direct-view device.
The front surface is transparent, as it is the portion of the device through which the viewer views the image. Manufacture of an interferometric modulator is somewhat similar to other types of devices manufactured on glass, such as liquid crystal devices (LCD). However, due to the unique nature of the device, packaging of the device has some other considerations.
Interferometric modulators are microelectromechanical systems (MEMS) devices. While they use a glass substrate like LCDs, they also have moving parts and must have room to move while remaining protected. Similarly, while they are MEMS devices, they are manufactured on a substrate that has different processing considerations than most MEMS devices.
There are some degrees of freedom available to interferometric modulators not available to either LCDs or many MEMS devices. Unlike LCDs, interferometric modulators do not have material injected into the package, such as the liquid crystalline material is into LCD display panels. Unlike many MEMS devices, interferometric modulators do not have parts that rub against one another, alleviating concerns about internal particle generation.