Inventors:
Marion B. Reine - Wellesley MA
Ronald R. Kusner - Concord MA
Assignee:
Honeywell, Inc. - Minneapolis MN
International Classification:
G01L 3108
Abstract:
The present invention is an improvement on the thermal imaging detector of Elliott (U. S. Pat. No. 3,995,195). This detector, which has come to be called the SPRITE detector (Signal PRocessing In The Element), is being applied in serially scanned thermal imaging systems for the 8-12 micrometer infrared spectral band. All such SPRITE detectors to date have been three terminal devices, including two bias contacts at either end of the detector, and one additional readout electrode which, together with the nearby bias contact, define the readout zone across which the integrated photoconductive signal voltage is measured. The present invention recognizes that using a bias contact as one of the two readout electrodes can substantially reduce the spatial frequency response of the SPRITE detector. Thus, the present invention utilizes a four-terminal SPRITE detector configuration in which readout is achieved in a differential manner across two voltage probes. The two voltage probes are located far enough away from the bias contacts so that the bias contacts do not degrade the spatial frequency response.