Infrared detector arrays
AssigneeVaro, Inc.
InventorCharles M. Hanson
Life of this patent
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Abstract
The capacitive bolometer comprises a detection capacitor having a first-order phase transistion ferroelectric material between two electrodes. The detection capacitor operates during a detection step and a subsequent readout step. During the detection step, a preselected electric field is applied to the detection capacitor to maximize its sensitivity to temperature. A second electric field is applied to the capacitor during the readout step in order to increase responsivity of the detection cell. The detection cells according to the invention can be assembled into disclosed detection arrays.
Claims26
A switched-capacitor infrared detector array, comprising:
- a plurality of ferroelectric capacitors disposed in a plurality of rows and columns, first switch means selectively connecting each ferroelectric capacitor to a detection voltage source, second switch means selectively connecting each ferroelectric capacitor with a reference capacitor, said reference capacitor having first been charged by temporary connection to a reference voltage source, said first switch means in each row being connected in common, said second switch means in each row being connected in common,
- means for each column for reading a voltage on a selected one of said ferroelectric capacitors in said column.
A switched-capacitor infrared detector array, comprising:
- a plurality of ferroelectric capacitors disposed in a plurality of rows and columns, first switch means selectively connecting each ferroelectric capacitor to a detection voltage source, second switch means selectively connecting each ferroelectric capacitor with a reference capacitor, said reference capacitor having first been charged by temporary connection to a reference voltage source, said first switch means in each row being connected in common, said second switch means in each row being connected in common;
- means for each column for reading a voltage on a selected one of said ferroelectric capacitors in said column;
- and
- said detection voltage source and said reference voltage source being of opposite polarity.
A switched-capacitor infrared detector array, comprising:
- a plurality of ferroelectric capacitors disposed in a plurality of rows and columns, first switch means selectively connecting each ferroelectric capacitor to a detection voltage source, second switch means selectively connecting each ferroelectric capacitor with a reference capacitor, said reference capacitor having first been charged by temporary connection to a reference voltage source, said first switch means in each row being connected in common, said second switch means in each row being connected in common;
- means for each column for reading a voltage on a selected one of said ferroelectric capacitors in said column;
- and
- said detection voltage selected to produce close to a maximum capacitance in each said ferroelectric capacitor.
A switched capacitor infrared detector array, comprising:
- a plurality of ferroelectric capacitors disposed in a plurality of rows and columns, first switch means for selectively coupling each ferroelectric capacitor to a reference voltage source, second switch means for selectively coupling each ferroelectric capacitor to a charge injection source, said first switch means in each row being connected in common, said second switch means in each row being connected in common;
- each column having a readout means for reading a voltage on a selected one of said ferroelectric capacitors in said column.
A method for detecting infrared radiation using an array of ferroelectric capacitors arranged in a plurality of columns and rows, comprising the steps of:
- connecting a first row of detection capacitors to a detection voltage source;
- isolating each detection capacitor in the row from the detection voltage source after the step of connecting;
- connecting each detection capacitor in the row with a respective reference capacitor after the step of isolating;
- reading the voltage present at each detection capacitor in the row;
- thereafter disconnecting each detection capacitor from its respective reference capacitor;
- reconnecting the detection capacitor to the detection voltage source;
- and
- repeating the above steps for the next row of the detection capacitor array.
A method for sensing infrared radiation using an array of ferroelectric capacitors arranged in a plurality of columns and rows, comprising the steps of:
- connecting each of a plurality of column lines to a voltage reference source at a first time;
- disconnecting a selected row of detection capacitors from the voltage reference source at a second time;
- connecting each of the detection capacitors of the selected row of detection capacitors to a respective column line at least as late as the second time;
- disconnecting the column lines from the voltage reference source at a third time after the second time;
- injecting an injection pulse onto each of the column lines at a fourth time after the third time, such that each of the detection capacitors exhibits a substantially lower capacitance;
- reading the voltage present on each column line shortly after the fourth time;
- thereafter reconnecting each of the column lines to a reference voltage source;
- reconnecting the selected row of capacitors to the reference voltage, and disconnecting the selected row of capacitors from respective column lines;
- and
- repeating the above steps for a next selected row.
Dependencies are inferred from the claim text.