Abstract: An imaging system includes a pixel that does not require a row select transistor. Instead, an operating voltage is selectively provided to the pixel's readout circuitry, and the readout circuitry provides output signals based on charge or voltage of a storage node. The operating voltage can be selectively provided to each row of a pixel array by a row driver. Each pixel includes a source follower transistor that provides an output signal on a column output line for readout. An anti-blooming transistor may be linked to each pixel's photosensor to provide an overflow path for electrons during charge integration, prior to transfer of charge to the pixel's storage node by a transfer transistor. Electrons not produced by an image are introduced to the photosensor prior to image acquisition, filling traps in the photosensor to reduce image degradation.

Abstract: A method of operating an imager pixel that includes the act of applying a relatively small voltage on the gate of a transfer transistor during a charge acquisition period. If a small positive voltage is applied, a depletion region is created under the transfer transistor gate, which creates a path for dark current electrons to be transferred to a pixel floating diffusion region. The dark electrons are subsequently removed by a pixel reset operation. If a small negative voltage is applied to the transfer gate, electrons that would normally create dark current problems will instead recombine with holes thereby substantially reducing dark current.

Abstract: An imaging system includes a pixel that does not require a row select transistor. Instead, an operating voltage is selectively provided to the pixel's readout circuitry, and the readout circuitry provides output signals based on charge or voltage of a storage node. The operating voltage can be selectively provided to each row of a pixel array by a row driver. Each pixel includes a source follower transistor that provides an output signal on a column output line for readout. An anti-blooming transistor may be linked to each pixel's photosensor to provide an overflow path for electrons during charge integration, prior to transfer of charge to the pixel's storage node by a transfer transistor. Electrons not produced by an image are introduced to the photosensor prior to image acquisition, filling traps in the photosensor to reduce image degradation.

Abstract: Embodiments of the present invention provide pixel cells with increased storage capacity, which are capable of anti-blooming operations. In an exemplary embodiment a pixel cell has an electronic shutter that transfers charge generated by a photo-conversion device to a storage node before further transferring the charge to the pixel cell's floating diffusion node. Each pixel cell also includes an anti-blooming transistor for directing excess charge out of each respective pixel cell, thus preventing blooming. Additionally, two or more pixel cells of an array may share a floating diffusion node and reset and readout circuitry.

Abstract: A method for automatically measuring the modulation transfer function of an imager is disclosed. A opaque mask is placed over selected columns and rows of the imager during fabrication. In the course of an automated process, photons are uniformly shone over the image sensor. The amount of the input signal that flows from the unmasked pixel cells to the masked pixel cells can then be measured and the modulation transfer function can be determined.

Abstract: A method of operating an imager pixel that includes the act of applying a relatively small voltage on the gate of a transfer transistor during a charge acquisition period. If a small positive voltage is applied, a depletion region is created under the transfer transistor gate, which creates a path for dark current electrons to be transferred to a pixel floating diffusion region. The dark electrons are subsequently removed by a pixel reset operation. If a small negative voltage is applied to the transfer gate, electrons that would normally create dark current problems will instead recombine with holes thereby substantially reducing dark current.

Abstract: An imaging system includes a pixel that does not require a row select transistor. Instead, an operating voltage is selectively provided to the pixel's readout circuitry, and the readout circuitry provides output signals based on charge or voltage of a storage node. The operating voltage can be selectively provided to each row of a pixel array by a row driver. Each pixel includes a source follower transistor that provides an output signal on a column output line for readout. An anti-blooming transistor may be linked to each pixel's photosensor to provide an overflow path for electrons during charge integration, prior to transfer of charge to the pixel's storage node by a transfer transistor. Electrons not produced by an image are introduced to the photosensor prior to image acquisition, filling traps in the photosensor to reduce image degradation.

Abstract: An imaging system includes a pixel that does not require a row select transistor. Instead, an operating voltage is selectively provided to the pixel's readout circuitry, and the readout circuitry provides output signals based on charge or voltage of a storage node. The operating voltage can be selectively provided to each row of a pixel array by a row driver. Each pixel includes a source follower transistor that provides an output signal on a column output line for readout. An anti-blooming transistor may be linked to each pixel's photosensor to provide an overflow path for electrons during charge integration, prior to transfer of charge to the pixel's storage node by a transfer transistor. Electrons not produced by an image are introduced to the photosensor prior to image acquisition, filling traps in the photosensor to reduce image degradation.

Abstract: An improved pixel cell is disclosed for use in an imager device, the pixel cell having increased signal to noise ratios, and a larger charge storage capacity. Each pixel cell contains two storage nodes in parallel with each other and also in series with the floating diffusion region. During applications requiring lower storage capacity, one of the storage nodes is activated. During applications requiring higher storage capacity, the second storage node is activated sequentially after the first storage node is activated. Thereafter, the full charge stored by both storage nodes is read out by the pixel readout circuit. Further, in accordance with an exemplary embodiment of the invention, one of the storage nodes is obtained by an additional transfer gate and diffusion node connected to a physical capacitor within the pixel cell and the other storage node is formed by a storage gate covering an additional depletion area between the photodiode and the floating diffusion region.

Abstract: Embodiments of the present invention provide pixel cells with increased storage capacity, which are capable of anti-blooming operations. In an exemplary embodiment a pixel cell has an electronic shutter that transfers charge generated by a photo-conversion device to a storage node before further transferring the charge to the pixel cell's floating diffusion node. Each pixel cell also includes an anti-blooming transistor for directing excess charge out of each respective pixel cell, thus preventing blooming. Additionally, two or more pixel cells of an array may share a floating diffusion node and reset and readout circuitry.

Abstract: A CMOS imaging system with increased charge storage capacitance of pixels yet decreased physical size, kTC noise and active area. A capacitor is linked to the transfer gate and provides a storage node for a pixel, allowing for kTC noise reduction prior to readout. The pixel may be operated with the shutter gate on during the integration period to increase the amount of time for charge storage by a pixel.

Abstract: A CMOS imaging system with increased charge storage of pixels yet decreased physical size, kTC noise and active area. A storage node is connected to the transfer gate and provides a storage node for a pixel, allowing for kTC noise reduction prior to readout. The pixel may be operated with the shutter gate on during the integration period to increase the amount of time for charge storage by a pixel.

Abstract: A method for automatically measuring the modulation transfer function of an imager is disclosed. A opaque mask is placed over selected columns and rows of the imager during fabrication. In the course of an automated process, photons are uniformly shone over the image sensor. The amount of the input signal that flows from the unmasked pixel cells to the masked pixel cells can then be measured and the modulation transfer function can be determined.

Abstract: An apparatus and method for controlling gain characteristics in a CMOS imager and for calibrating light intensity and analog to digital conversion in a pixel array. A mask with varying sized apertures is provided over pixels of an array outside the active area for use in intensity adjustments and calibration.