Method and device for reading electrical charges produced by a photo-detector, and detector comprising such devices
AssigneeSociete Francaise de Detecteurs Infrarouges-Sofradir
InventorEric Sanson
Life of this patent
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Abstract
A method of reading electrical charges produced by a photo-detector of a photo-detector matrix includes collecting and storing electrical charges produced by the photo-detector in a first capacitive element, transferring the charges stored in the first capacitive element to a second capacitive element, and reading the voltage at the terminals of the second capacitive element. The transfer followed by the reading is carried out in at least two phases: at least one first phase taking place during the collection and storage of the charges in the first capacitive element, and a second phase taking place at the end of the collection and storage of the electrical charges in the first capacitive element.
Claims9
A method for reading electrical charges produced by a photo-detector of a photo-detector matrix by integrating said charges during an integration period, thereby producing an output voltage, and reading the output voltage, said method comprising:
- collecting and storing said charges in a first capacitive element during the integration period;
- transferring the charges stored in the first capacitive element during the integration period to a second capacitive element;
- and
- reading the output voltage at the terminals of the second capacitive element,
- wherein the transfer of the charges stored in the first capacitive element during the integration period is carried out in at least two phases:
- at least one first phase taking place during the collection and storage of the charges in the first capacitive element;
- and
- a second phase taking place at the end of the collection and storage of the electrical charges in the first capacitive element, and
- wherein said step of reading the voltage at the terminals of the second capacitive element results from each transfer of the charges during the integration period, thereby providing for the integration period at least one intermediate voltage in addition to the output voltage.
A device for reading electrical charges produced by a photo-detector of a photo-detector matrix by integrating said charges during an integration period, thereby producing an output voltage, and reading the output voltage, said device comprising:
- a first and a second capacitive elements;
- an injection circuit capable, when it is enabled, of biasing the photo-detector and capable of transferring the charges produced thereby to the first capacitive element;
- a controllable switch, capable in its closed state, of transferring the charges stored in the first capacitive element to the second capacitive element;
- a read circuit capable of reading the voltage at the terminals of the second capacitive element;
- and
- and a control circuit capable of controlling the switch in order to transfer the charges from the first capacitive element to the second capacitive element,
- wherein the control circuit is capable of closing the switch, and then controlling the reading of the charges stored in the second capacitive element during the course of at least two phases of the integration period, at least one first phase taking place while the injection circuit is enabled, and a second phase taking place at the end of integration, before or after the injection circuit is disabled, and
- wherein the read circuit reads the voltage at the terminals of the second capacitive element resulting from each transfer of the charges during the integration period, thereby providing for the integration period at least one intermediate voltage in addition to the output voltage.
Dependencies are inferred from the claim text.