Matrix array image sensor chip
First Claim
1. An integrated circuit for use as an image array sensor and providing an output signal to an off-circuit read device, said integrated circuit comprising,a two-dimensional matrix array of sensing cells having a plurality of cell columns and a plurality of cell rows, each sensing cell having a photodiode and a transistor for reading from and writing to the photodiode,horizontal scan means coupled to each cell in the array for scanning each cell row of the array of sensing cells,vertical scan means coupled to each cell in the array for scanning each cell column of said array of sensing cells,a plurality of analogue switch means each connected between at least one of said cell columns and the horizontal scan means for receiving image data from said cells, each of said analogue switch means being also connected by a common conductor to an output amplifier forming the output of the integrated circuit, each of said plurality of analogue switch means includes voltage storage means and first charge sensing amplifier means which provides a preliminary detection of charge created on each cell in response to radiation impinging thereon by converting the detected charge to a voltage using a first charge integrating circuit and capacitively storing the voltage in said voltage storage means, in the form of a charge corresponding to the cell charge, and that said output amplifier comprises a second charge sensing amplifier means which is selectively coupled to said voltage storage means of said analogue switch means, for providing an output signal to the off-circuit read device, said output signal being a voltage proportional to the charge in said voltage storage means.
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Abstract
A matrix array image sensor integrated circuit chip is provided including horizontal and vertical scanning means with the sensor cells within columns of the array being associated with an analogue charge sense amplifier. The analogue charge sense amplifier includes a first amplifier in the form of an inverting charge integrator which provides a preliminary detection of the charge accumulated in the sensing cell by integrating the charge to produce a voltage which is capacitively stored in a voltage storage means. The sensing cell may then be reset by control logic while it is isolated from the stored voltage which is in turn selectively sampled using a switch to read out through a second amplifier stage to be provided as an output from the integrated circuit chip. A method for operation of the device in processing an image read cycle is also provided.
219 Citations
20 Claims
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1. An integrated circuit for use as an image array sensor and providing an output signal to an off-circuit read device, said integrated circuit comprising,
a two-dimensional matrix array of sensing cells having a plurality of cell columns and a plurality of cell rows, each sensing cell having a photodiode and a transistor for reading from and writing to the photodiode, horizontal scan means coupled to each cell in the array for scanning each cell row of the array of sensing cells, vertical scan means coupled to each cell in the array for scanning each cell column of said array of sensing cells, a plurality of analogue switch means each connected between at least one of said cell columns and the horizontal scan means for receiving image data from said cells, each of said analogue switch means being also connected by a common conductor to an output amplifier forming the output of the integrated circuit, each of said plurality of analogue switch means includes voltage storage means and first charge sensing amplifier means which provides a preliminary detection of charge created on each cell in response to radiation impinging thereon by converting the detected charge to a voltage using a first charge integrating circuit and capacitively storing the voltage in said voltage storage means, in the form of a charge corresponding to the cell charge, and that said output amplifier comprises a second charge sensing amplifier means which is selectively coupled to said voltage storage means of said analogue switch means, for providing an output signal to the off-circuit read device, said output signal being a voltage proportional to the charge in said voltage storage means.
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8. A method of detecting radiation incident upon an image sensor fabricated using integrated circuit technology in which the integrated circuit comprises a two dimensional matrix array of image sensing cells having a plurality of cell columns and a plurality of cell rows, each image sensing cell having a photodiode and a transistor for reading to and writing from the photodiode, horizontal scan means coupled to each cell in the array for scanning each cell row in the array, vertical scan means coupled to each cell in the array for scanning each cell column in the array, and a plurality of analogue switch means each connected between at least one of the cell columns and said horizontal scan means for receiving image data from each of said cells, each of said plurality of analogue switch means includes voltage storage means and first charge sensing amplifier means, each of said analogue switch means being also connected by a conductor to a output amplifier having its output connected to an external read-device for reading image signals from said output amplifier, said method being characterized by the steps of:
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reading a cell from an associated one of said cell columns using a selected one of the plurality of analogue switch means by generating a voltage to balance charge in the cell created in response to incident radiation, storing the voltage capacitively in the selected one of the plurality of analogue switch means in the form in the form of a charge corresponding to the cell charge, and reading out the capacitively stored information in the selected one of the plurality of analogue switch means to the output amplifier. - View Dependent Claims (9)
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19. An integrated circuit image array sensor comprising:
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a two-dimensional matrix array of sensing cells having a plurality of cell columns and a plurality of cell rows, each of said sensing cells in said two-dimensional matrix array having a photodiode and a transistor for reading from and writing to the photodiode, each of said sensing cells in said two-dimensional matrix array generating a charge in response to radiation impinging on said cell to provide image data; horizontal scan means coupled to each cell in said two-dimensional matrix array for scanning each cell row of the array of sensing cells; vertical scan means coupled to each cell in said two-dimensional matrix array for scanning each cell column of said array of sensing cells; a plurality of analogue switch means each connected between at least one of said cell columns and said horizontal scan means for receiving said image data from said cells, each of said analogue switch means including charge sensing amplifier means for converting said charge to a voltage by integrating said charge and further including a voltage storage means for capacitively storing said voltage; and an output amplifier which is selectively connected to each of said voltage storage means.
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20. An integrated circuit for use as an image array sensor and providing an output signal to an off-circuit read device, said integrated circuit comprising,
a two-dimensional matrix array of sensing cells having a plurality of cell columns and a plurality of cell rows, each sensing cell having a photodiode and a transistor for reading from and writing to the photodiode, horizontal scan means coupled to each cell in the array for scanning each cell row of the array of sensing cells, vertical scan means coupled to each cell in the array for scanning each cell column of said array of sensing cells, a plurality of analogue switch means each connected between at least one of said cell columns and the horizontal scan means for receiving image data from said cells, each of said analogue switch means being also connected by a common conductor to a output amplifier forming the output of the integrated circuit, each of said plurality of analogue switch means includes voltage storage means and first charge sensing amplifier means which provides a preliminary detection of charge created on each cell in response to radiation impinging thereon by converting the detected charge to a voltage using a first charge integrating circuit, said first charge integrating circuit comprising an inverter means for generating a voltage to balance said charge created on each cell, and capacitively storing the voltage in said voltage storage means, in the form of a charge corresponding to the cell charge, and that said output amplifier comprises a second charge sensing amplifier means which is selectively coupled to said voltage storage means of said analogue switch means, for providing an output signal to the off-circuit read device, said output signal being a voltage proportional to the charge in said voltage storage means.
Specification