Prof. P. Apte of Department of Electrical Engineering and his colleague of Department of Mechanical Engineering and their students from have been able to develop an opto-thermo-mechanical integrated uncooled imaging system that captures the thermal images for direct coloured display of thermal images. Thermal imaging is used in applications such as night vision, environmental monitoring, astronomy, biomedical diagnostics, and thermal probing of microelectronic devices.

The invention collects infrared radiation which passes through an infrared lens system and forms an image onto the device. The system works in the following way. IR radiation passes through a special substrate in the lower diaphragm and gets absorbed in the upper diaphragm of the array. The heat absorbed gets conducted to the substrate through displaceable bimorph members linked to the diaphragm. Heated bimorph members cause deflection that raises the upper diaphragm.

White light incident on the upper diaphragm causes constructive interference of a specific colour in visible light range. The end result of this process is that a direct colour image can be generated.

Some features:
- IR sensing and coloured image display capability
- Room temperature operation
- No cryogenic cooling equipment required
- Inherent room temperature compensation
- No further image processing of captured IR images needed

A direct coloured display of images is formed by the system without any processing device or electronics, intervening electronics or electrical connections and reduced thermal cross-talk between neighbouring pixels. No internal heat is generated due to the absence of electrical current. The device is simple and robust and has minimal number of parts.

Indian patent application no. 541/MUM/2005 Patent grant no. 236126
Inventors: P Apte, B Seth, O Karhade, and S Chiluveru