This thesis presents the development of integrated readout electronics for diode type microbolometers
and development of external camera electronics for microbolometers. The
developed readout electronics are fabricated with its integrated 160x120 resolution FPA (Focal
Plane Array) in the XFAB SOI-CMOS 1.0 &mu / m process. The pixels in the FPA have 70 &mu / m
pixel pitch, and they are sensitive in the 8&ndash / 12 &mu / m band of the infrared spectrum. Each pixel
has 4 serially connected diodes, and diode turn on voltage changes as the temperature of the
suspended and thermally isolated pixel increases due to the absorbed infrared power. Suspension
of the pixels is obtained with a post-CMOS MEMS etching process, but this process
requires no critical litography and/or deposition steps. This dramatically reduces the detector
process cost, which makes this microbolometer FPA suitable for ultra low-cost applications
such as automobile, security, and commercial applications. The readout electronics of the
FPA include digital blocks such as timing and programming blocks as well as analog blocks
such as a differential trans-conductance amplifier, a switched capacitor integrator, a sampleand-
hold, and current DACs. This new readout design has reduced number of pins to simplify
the external electronics and allows wafer-level vacuum packaging compared to the 128x128
FPA developed in a previous study at METU with the same approach. Both of these features
further decrease the cost.
Two kinds of external camera electronics are developed for two SOI type microbolometers.
The first one is for the 128x128 SOI microbolometer previously designed in METU. The
developed external camera electronics have 1.5mVrms noise, which is much less than the microbolometer
noise. The overall system has an average NETD of 465 mK and a peak NETD
of 320mK. The second developed external camera electronics are for the 160x120 SOI microbolometers
that developed in the scope of this thesis. The developed external camera electronics
has 0.55mVrms noise which is much less than the bolometer noise which is 5mVrms.
The overall system has an average NETD of 820 mK and a peak NETD of 350 mK. Each
of these external camera electronics include a custom designed PCB, an FPGA board with
appropiate configurion and a software working on a PC. The custom designed PCB holds
the external components for the microbolometer, an FPGA takes and processes the bolometer
data and it sends to a PC, and a PC processes these data and forms a streaming video. These
two external camera electronics allow to obtain human images verifying that the developed
microbolometers can be used for security and automotive applications.
| Identifer | oai:union.ndltd.org:METU/oai:etd.lib.metu.edu.tr:http://etd.lib.metu.edu.tr/upload/12613082/index.pdf |
| Date | 01 February 2011 |
| Creators | Akcoren, Dincay |
| Contributors | Akin, Tayfun |
| Publisher | METU |
| Source Sets | Middle East Technical Univ. |
| Language | English |
| Detected Language | English |
| Type | M.S. Thesis |
| Format | text/pdf |
| Rights | To liberate the content for public access |
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