JAPAN: OMRON Corp. has finished development work on the world's first infrared sensor manufactured with wafer-level vacuum packaging technology to create a 16x16 element MEMS non-contact infrared thermal sensor capable of highly precise 90-degree area detection. Shipping of test samples will commence in October 2013.
In recent years the demand for human presence sensors has been growing in tandem with the demand for energy-efficient "smart home" and "smart office" environments in which lighting, heating, etc. is automatically controlled according to where people are positioned.
Since conventional pyroelectric human presence sensors (motion sensors) are only able to detect people when they are in motion, they are not as suitable for detecting the number of people in a certain space or their relative positions as Omron's new thermal sensor.
MEMS non-contact thermal sensors measure temperature by converting infrared energy radiated from target objects into heat with MEMS thermopiles and then measuring the thermoelectromotive force resulting from temperature differences that occur across the contact points of two different types of metal. However, up till now it has not been possible to create large temperature differences across the metal contact points because much of the heat generated by the thermopiles dissipates into the surrounding air, meaning that the resulting thermoelectromotive force is reduced thereby limiting sensitivity.
Omron has solved this heat dissipation problem by vacuum sealing the thermopiles inside the chip – the first time this has been achieved. The reduction in heat dissipation leads to a greater temperature difference across the metal contacts thereby increasing sensitivity.
Omron will now also work on commercializing stand-alone human presence sensor modules by combining non-contact thermal sensors with algorithms that can accurately distinguish the number of people and their positions within a detected space.