A digital pixel includes a capacitive transimpedence amplifier (CTIA) coupled to a photodiode that receives an electrical charge and output an integration voltage. An integration capacitor coupled to the CTIA accumulates the integration voltage over an integration period. A comparator compares the accumulated integration voltage with a threshold voltage and generates a control signal at a first level each time the accumulated integration voltage is greater than the threshold voltage. A charge subtraction circuit receives the control signal at the first level and discharges the accumulated integration voltage each time the control signal at the first level is received from the comparator. An analog or digital counter receives the control signal at the first level and adjusts a counter value each time the control signal is received from the comparator. An output interface communicates the counter value to an image processing circuit at an end of the integration period.

A pixel circuit for a ultra-low power image sensor, including: an integration node, on which a photodiode current is integrated, a comparator arranged to compare a voltage at the integration node with a reference voltage, a n+1 bits digital memory, a writing pulse signal generator arranged to generate a writing pulse signal, on the basis of the comparator output voltage and on the voltage at a memory node, the start of the pulse triggering the writing of the digital word in the n-bits digital memory part. The comparator includes a switch in series with a current source and arranged to be commanded by the voltage at the memory node so that the switch is open at the end of the pulse, so as to drastically limit the consumption of static power of the pixel circuit during the integration phase.

In one example, an apparatus is provided. The apparatus comprises an image sensor configured to generate a first raw output to represent a first intensity of incident light based on a first relationship, and to generate a second raw output to represent a second intensity of incident light based on a second relationship. The apparatus further comprises a post processor configured to: generate a first post-processed output based on the first raw output and based on the first relationship such that the first post-processed output is linearly related to the first intensity based on a third relationship, and to generate a second post-processed output based on the second raw output and based on the second relationship such that the second post-processed output is linearly related to the second intensity based on the third relationship.

An imaging device including a pixel array including pixels, each pixel including a photoelectric converter including a first and second electrode, and a first photoelectric conversion layer between the first and second electrode, and a transistor having a gate coupled to the first electrode, the transistor outputting a signal corresponding to an amount of the signal charge collected by the first electrode. The device further including voltage supply circuitry coupled to the second electrode of each of the pixels, where the voltage supply circuitry, in each of consecutive frame periods, supplies a first voltage two or more times to form exposure periods in which the signal charge is collected by the first electrode, and supplies a second voltage one or more times to form non-exposure periods that separate the exposure periods from each other, and start time of each of the exposure periods is periodic over the consecutive frame periods.

An imaging device including a pixel array including pixels, each pixel including a photoelectric converter including a first and second electrode, and a first photoelectric conversion layer between the first and second electrode, and a transistor having a gate coupled to the first electrode, the transistor outputting a signal corresponding to an amount of the signal charge collected by the first electrode. The device further including voltage supply circuitry coupled to the second electrode of each of the pixels, where the voltage supply circuitry, in each of consecutive frame periods, supplies a first voltage two or more times to form exposure periods in which the signal charge is collected by the first electrode, and supplies a second voltage one or more times to form non-exposure periods that separate the exposure periods from each other, and start time of each of the exposure periods is periodic over the consecutive frame periods.

A method of operating an HDR pixel circuit includes: establishing a calibration full-well capacity of a photodiode according to a first predetermined voltage level; over-charging both the photodiode and a floating diffusion node; dissipating the charges of the floating diffusion node and the charges on the photodiode so that the charges on the photodiode are substantially equal to the calibration full-well capacity; transferring the charges on the photodiode to the floating diffusion node; and sensing a voltage on the floating diffusion node to generate a calibration signal related to the calibration full-well capacity.

A camera system including a photoelectric convertor including a first and second electrode, and a photoelectric conversion layer; and a correction circuit correcting a signal corresponding to a potential change of the second electrode. The photoelectric convertor has a photoelectric conversion characteristic in which rate of change of the photoelectric conversion efficiency with respect to a first bias voltage between the first electrode and the second electrode when the first bias voltage is in a first voltage range, is greater than the rate of change with respect to a second bias voltage when the second bias voltage is in a second voltage range that is higher than the first voltage range, and a bias voltage between the first electrode and the second electrode exists in the first voltage range, and the correction circuit corrects the signal so that variation of an output regarding an amount of incident light becomes linear.

The present disclosure relates to an image sensor comprising a plurality of pixel circuits each comprising a photodiode connected between ground and a floating diffusion (FD) node, a reset transistor (MRST) connected between a first voltage supply and the floating diffusion (FD) node, and a source follower transistor (MSF), wherein its drain is connected to a second voltage supply, the gate is connected to a floating diffusion (FD) node and the source is connected to a row select transistor (MSEL). The row select transistor (MSEL) is connected between the source of the source follower transistor (MSF) and a common column output. Each pixel circuit is configured to output an output signal corresponding to a light incident on the photodiode. Each pixel circuit includes at least one additional transistor for configuring each pixel circuit to selectively output a linear integration signal or a logarithmic signal.

A high dynamic range image sensors enabled by integrating broadband optical filters with individual sensor pixels of a pixel array. The broadband optical filters are formed of engineered micro or nanostructures that exhibit large differences in transmittance, e.g. up to 5 to 7 orders of magnitude. Such high transmittance difference can be achieved by using a single layer of individually designed filters, which show varied transmittance as a result of the distinct absorption of various material and structures. The high transmittance difference can also be achieved by controlling the polarization of light and using polarization-sensitive structures as filters. With the presence of properly designed integrated nanostructures, broadband transmission spectrum with transmittance spanning several orders of magnitude can be achieved. This enables design and manufacturing of image sensors with high dynamic range which is crucial for applications including autonomous driving and surveillance.

A method of operating an HDR pixel circuit includes: establishing a calibration full-well capacity of a photodiode according to a first predetermined voltage level; over-charging both the photodiode and a floating diffusion node; dissipating the charges of the floating diffusion node and the charges on the photodiode so that the charges on the photodiode are substantially equal to the calibration full-well capacity; transferring the charges on the photodiode to the floating diffusion node; and sensing a voltage on the floating diffusion node to generate a calibration signal related to the calibration full-well capacity.