Abstract: A pixel sensor having a main photodetector and a parasitic photodiode and a method for reading out that pixel sensor are disclosed. The pixel sensor is read by reading a first potential on a floating diffusion node in the pixel sensor while the floating diffusion node is isolated from the main photodiode. The pixel sensor is then exposed to light such that the floating diffusion node and the photodetector are both exposed to the light. A second potential on the floating diffusion node is then readout while the floating diffusion node is isolated from the main photodiode. After the first and second potentials are readout, a third potential on the floating diffusion node is readout. The main photodiode is then connected to the floating diffusion node, and a fourth potential on the floating diffusion node is readout. First and second light intensities are determined from the readout potentials.

Abstract: A column readout amplifier and imaging array using the same method are disclosed. The column readout amplifier includes a signal amplifier having an amplifier signal output, a first filter capacitor, a buffer amplifier having a buffer amplifier input and a buffer amplifier output, and a switching network. The switching network connects the amplifier signal output to the buffer amplifier input and the buffer amplifier output to the first filter capacitor during a first time period, and connects the amplifier signal output directly to the first filter capacitor during a second time period. The time periods can be of fixed duration or determined by the difference in potential between the input and output of the buffer amplifier. The column readout amplifier can be used in an imaging array to readout columns of pixels.

Abstract: An imaging sensor using a novel bit line processing circuit, that circuit, and the method of processing the pixel outputs from an image sensor using that processing circuit are disclosed. The image sensor includes an array of pixel sensors, a signal digitizing circuit, and a digitizing controller. Each pixel sensor generates a voltage signal that is a function of a charge on the photodetector in that pixel sensor, and couples that voltage signal to a bit line in response to a first signal. The signal digitizing circuit is connected to the bit line, the digitizing circuit converting the voltage signal to a plurality of output digital values, the output digital values having selectable levels of digitization noise. The digitizing controller generates the level of noise based on the voltage signal. The signal digitizing circuit includes a variable gain amplifier and an ADC having a fixed number of bits.

Abstract: An imaging sensor using a novel bit line processing circuit, that circuit, and the method of processing the pixel outputs from an image sensor using that processing circuit are disclosed. The image sensor includes an array of pixel sensors, a signal digitizing circuit, and a digitizing controller. Each pixel sensor generates a voltage signal that is a function of a charge on the photodetector in that pixel sensor, and couples that voltage signal to a bit line in response to a first signal. The signal digitizing circuit is connected to the bit line, the digitizing circuit converting the voltage signal to a plurality of output digital values, the output digital values having selectable levels of digitization noise. The digitizing controller generates the level of noise based on the voltage signal. The signal digitizing circuit includes a variable gain amplifier and an ADC having a fixed number of bits.

Abstract: A pixel sensor having a main photodiode and a parasitic photodiode and a method for reading out that pixel sensor are disclosed. The parasitic photodiode also serves the function of a floating diffusion node in the pixel. The pixel sensor is read by first determining the exposure as measured by the parasitic photodiode and then determining the exposure as read by the main photodiode. One of the two exposure measurements is chosen as the pixel output. The main photodiode has a light conversation efficiency chosen such that one of the two measurements will provide a measurement of the exposure over a dynamic range that is greater than that of either the main photodiode or the parasitic photodiode utilized separately.

Abstract: A sample and hold circuit and a method for sampling a signal are disclosed. The sample and hold circuit includes first and second switches, first, second, and third capacitors, and an amplifier. The amplifier receives a signal to be sampled on a first input. The first capacitor is characterized by a first capacitance and has a first terminal connected to an output of the amplifier by the first switch. The second capacitor is characterized by a second capacitance and has a second terminal connected to the output of the amplifier by the second switch. The third capacitor connects the first and second terminals. The amplifier is configured to form a capacitive transimpedance amplifier having the third capacitor as a feedback circuit when the first switch is in a non-conducting state and the second switch is in a conducting state.

Abstract: An image sensor that includes a first imaging array and a FPGA processor that processes images captured by the imaging array to provide information about the scene projected on the first imaging array is disclosed. The FPGA processor is connected to the first imaging array and includes an interface for receiving images from the first imaging array and an interface to an image storage memory that stores a plurality of images. The FPGA implements a plurality of image processing functions in the gates of the FPGA. The image processing functions processing one of the images stored in the image storage memory to extract a quantity related to the one of the images. The FPGA also includes an I/O interface used by the FPGA to output the quantity to a device external to the image sensor.

Abstract: A sample and hold circuit and a method for sampling a signal are disclosed. The sample and hold circuit includes first and second switches, first, second, and third capacitors, and an amplifier. The amplifier receives a signal to be sampled on a first input. The first capacitor is characterized by a first capacitance and has a first terminal connected to an output of the amplifier by the first switch. The second capacitor is characterized by a second capacitance and has a second terminal connected to the output of the amplifier by the second switch. The third capacitor connects the first and second terminals. The amplifier is configured to form a capacitive transimpedance amplifier having the third capacitor as a feedback circuit when the first switch is in a non-conducting state and the second switch is in a conducting state.

Abstract: A camera adapted for taking pictures of a moving scene is disclosed. The camera includes an imaging array, a plurality of charge-coupled device (CCD) shift registers, and a controller. The imaging array includes a plurality of CMOS pixel sensors organized as a plurality of columns and rows. The image moves in the column direction. One CCD shift register corresponds to each of the columns. Each CMOS pixel sensor includes a first transfer gate that transfers charge accumulated in the pixel sensor to a corresponding cell in the CCD shift register. The controller controls the CCD shift registers such that charge stored in a first cell in a CCD shift register is moved to a second cell in the CCD shift register where the charge is combined with charge accumulated by the pixel sensor that is connected to the second cell, the combined charge being generated from the same image pixel.

Abstract: An apparatus and method for forming a digital image are disclosed. The apparatus includes a plurality of pixel sensors and a controller. Each sensor includes a photodiode, a floating diffusion node that can be selectively connected to said photodiode or a reset voltage, and an analog-to-digital converter (ADC) connected to the floating diffusion node, the ADC converting a voltage on the floating diffusion node to a digital value. Each pixel sensor also includes an output circuit that connects the ADC to a bus. The apparatus also includes a controller that causes the ADCs to operate in parallel to convert the voltages on the floating diffusion nodes to the digital values in a time that is less than the time needed for the floating diffusion node to acquire ten electron equivalents of noise. The optional apparatus includes circuitry that allows correlated double sampling to be performed in each sensor.

Abstract: An imaging array and a method for operating the same are disclosed. The imaging array includes a plurality of light pixels and a sense amplifier. Each light pixel includes a photodetector that generates and couples a signal indicative of a light exposure to a light pixel node, a readout circuit, and a mixer that mixes a signal on the light pixel node with a pixel oscillator signal. The sense amplifier includes an input node that receives a signal from each light pixel, one light pixel at a time. The sense amplifier also includes a high pass filter that attenuates signals with frequencies less than a cutoff frequency and a mixer that demodulates the signal from the filter to provide a signal that is related to the potential on the light pixel node of the light pixel connected to the first input node.

Abstract: An imaging array and method for using the same to capture an image are disclosed. The imaging array includes an array of pixel sensors and a controller. Each pixel sensor includes a dual-ported photodiode characterized by ports having first and second gates, and a charge conversion circuit. The charge conversion circuit generates a signal that is a function of a charge on the dual-ported photodiode when the first gate in the dual-ported photodiode is activated to transfer a charge on the dual-ported photodiode to the charge conversion circuit. The controller applies a potential to the second gates and measures a current flowing out of the second gates, each second port passing charge stored in the photodiode connected to the second port when a potential in the photodiode exceeds the applied potential. The controller determines an average light intensity incident on the array of pixel sensors.

Abstract: An imaging array and method for capturing an image utilizing the same are disclosed. The imaging array includes an array of pixel sensors in which each pixel includes a dual-ported photodiode or photogate and a charge conversion circuit. The charge conversion circuit generates a voltage signal that is a function of a charge on the dual-ported photodiode. The controller applies a potential that varies over the exposure to the second gates in the dual-ported photodiodes, each second port passing charge stored in the photodiode connected to the second port when a potential in the photodiode exceeds the applied potential. The potential is chosen such that charge flows through the second gates of pixel sensors that are exposed to light intensities greater than a first threshold intensity during the exposure.

Abstract: A CCD containing circuit and method for making the same. The circuit includes a CCD array and a protection circuit. The CCD array is constructed on an integrated circuit substrate and includes a plurality of gate electrodes that are insulated from the substrate by an insulating layer. The gate electrodes are connected to a conductor bonded to the substrate. The protection circuit is also constructed on the substrate. The protection circuit is connected to the conductor and to the substrate and protects the CCD array from both negative and positive voltage swings generated by electrostatic discharge events and the like. The protection circuit and the CCD can be constructed in the same integrated circuit fabrication process.

Abstract: A light sensor having a light conversion element between first and second electrodes is disclosed. The light conversion element includes a body of semiconductor material having first and second surfaces. The body of semiconductor material is of a first conductivity type and has doping elements in a concentration gradient that creates a first electrostatic field having a magnitude that varies monotonically from the first surface to the second surface. A bias circuit applies a variable potential between the first and second electrodes to create a second electrostatic field having a direction opposite to that of the first electrostatic field and a magnitude determined by the potential. One of the electrodes is transparent to light in a predetermined band of wavelengths. The body of semiconductor material can include an epitaxial body having a monotonically increasing concentration of a doping element as a function of the distance from one the surfaces.