Uncooled thermal cameras sell due to cheaper microbolometers

In this report, Yole’s analysts also highlighted consumer applications, stating that this market moved to a new phase of growth in 2013- 2014. Under this context, FLIR introduced in 2014, two disruptive technologies: the LEPTON core and FLIR ONE smartphone plugin. “A high number of pre-release reservations for FLIR ONE  (more than 30,000 units in July 2014) already confirms the commercial success of this innovation”, says Yole.

System Plus Consulting, a sister company of Yole, specialising in technology, electronic components and systems cost analysis, looked into FLIR’s products and proposes today a complete teardown analysis, entitled FLIR Systems FLIR ONE & LEPTON Consumer Thermal Imager with Microbolometer. System Plus’ report details the BOM, the manufacturing process flow and related cost analysis, the supply chain evolution and a comparison with FLIR i7 infrared camera and microbolometer sensors.

FLIR is a long wave IR camera manufacturer and main microbolometer supplier, and as such it drives the price war in the commercial market. “FLIR’s strategy is to take volume leadership in multiple markets, make economies of scale and further decrease price”, explains Michel Allain, CEO, System Plus. “To achieve this it exploits a vertically integrated business model and a fabless structure, with manufacturing subcontracted to ON Semiconductor”, he adds.

FLIR also boosted that strategy by acquiring Indigo System’s IR imager business in 2004 and Tessera’s Digital Optics wafer-level optics division in 2013.

This year, the company released two innovative solutions: the Lepton core and FLIR ONE smartphone plugin. Plugged into the back of an IPhone 5 or 5S, the FLIR ONE is the first consumer thermal camera featuring LWIR technology. It contains a visible VGA (640x480) camera and a thermal camera which provide images blended using FLIR MSX Technology.

The thermal camera uses FLIR’s Lepton core, where costs have been reduced in every element. The most expensive component, the sensor, is an uncooled vanadium oxide (VO) microbolometer featuring an 80x60 pixel resolution with 17µm pixel size. VO provides a high TCR and low 1/f noise, resulting in excellent thermal sensitivity and stable uniformity.

The microbolometer array is grown monolithically on top of a readout integrated circuit comprising the complete focal plane array. An anti-reflection coated window is bonded above the sensor array via a WLP process, encapsulating the array in a vacuum. The purpose of the vacuum is to provide high thermal resistance between the microbolometer elements and the ROIC substrate, allowing for maximum temperature change in response to incident radiation.

The system electronics that receive and process the signal is a custom ASIC device mounted in flipchip on the substrate. Digital Optics’ WLO brings an important part of the cost reduction. The silicon lenses are made at the wafer level with lithography and etching processes.

The final cost reduction comes from the core housing, which is a three-dimensional moulded interconnected device. Incorporating a conductive circuit pattern inside the housing provides grounding and allows FLIR to integrate a temperature sensor. “Thanks to its strong integration at the core level with WLO, WLP and custom ASIC use, the FLIR Lepton is the world's smallest microbolometer-based thermal imaging camera core”, comments Romain Fraux, Project Manager, MEMS Devices, ICs and Advanced Packaging, System Plus.