System and method of testing humidity in a sealed MEMS device

A method of testing humidity, comprising:

• providing a device which encloses i) a plurality of interferometric modulators and ii) a desiccant, wherein the desiccant is configured to change its color based on an amount of water vapor absorbed therein;
• determining a degree of a color change of the desiccant;
• and
• determining a relative humidity value inside the device based at least in part upon the determined degree of the color change.

A method of manufacturing a microelectromechanical systems (MEMS) device, the method comprising:

• providing a substrate;
• forming a plurality of interferometric modulators on the substrate;
• providing a desiccant configured to change its color based on an amount of water vapor absorbed therein;
• providing a backplate;
• and
• joining the substrate and the backplate so as to form a device which encloses the plurality of interferometric modulators and the desiccant,
• wherein the backplate includes at least one transparent portion through which the color change of the desiccant can be viewed from the outside of the device, and wherein a relative humidity value inside the MEMS device is determined based at least in part upon the determined degree of the color change.

A microelectromechanical systems (MEMS) device, comprising:

• a substrate;
• a plurality of interferometric modulators formed on the substrate;
• a desiccant configured to change its color based on an amount of water vapor absorbed
• therein;
• and
• a backplate,
• wherein the substrate and backplate are joined to each other so as to form a device which encloses the plurality of interferometric modulators and the desiccant,
• wherein the backplate includes at least one transparent portion through which the color change of the desiccant can be viewed from the outside of the device, and wherein a relative humidity value inside the MEMS device is determined based at least in part upon the determined degree of the color change.