Mercury cadmium telluride is important in the detection
of electromagnetic radiation in the eight to twelve micron
atmospheric window for infrared imaging systems. High
resolution infrared imaging systems use either large (256x256
element to 1024x1024 element) staring arrays or much smaller
(1-6 element) scanned arrays in which the image is optically
scanned across the detectors. In scanned arrays, high
resolution and sensitivity may result in the scan direction
not being parallel to the detector bias current.
The response of an infrared detector to uniform
illumination is investigated. It is found that variations in
the detector thickness result in significant changes in output
voltage.
Scanned detectors are modeled in five different
orientations; scan parallel to bias, scan opposite to bias,
scan perpendicular to bias, and two orientations of the scan
diagonal to the bias. The response is analyzed for two cases:
1) the size of the scanned radiation equal to the size of the
detector and 2) when the pixel width is half of the width of
the detector, but of equal length.
Results of the simulation show that the fastest response
occurs when the scan and bias are parallel. The largest
response occurs when the scan direction is diagonal to the
bias, but the response time is much slower than when the bias
is parallel to the scan. Therefore, a tradeoff must be made
between maximum signal and speed of response.
Test detectors are being fabricated and will be tested at
FLIR Systems Inc., Portland, Oregon, to confirm the model
predictions. / Graduation date: 1992
| Identifer | oai:union.ndltd.org:ORGSU/oai:ir.library.oregonstate.edu:1957/37295 |
| Date | 19 December 1991 |
| Creators | Reudink, Mark D. |
| Contributors | Plant, Thomas K. |
| Source Sets | Oregon State University |
| Language | en_US |
| Detected Language | English |
| Type | Thesis/Dissertation |
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