Abstract: A pixel array includes a plurality of pixel structures, with each pixel structure having a photo-sensitive element for generating charge in response to incident light; a charge conversion element; a first transfer gate and a second transfer gate connected in series between the photosensitive element and the charge conversion element or between the photosensitive element and a supply line; and an output stage. A first transfer gate control line is connected to the first transfer gates of a first sub-set of the pixel structures in the array; and a second transfer gate control line connected to the second transfer gates of a second sub-set of the pixel structures in the array. The first sub-set of pixel structures and second sub-set of pixel structures partially overlap, having at least one pixel structure in common between them.

Abstract: A pixel structure comprises a photo-sensitive element for generating charge in response to incident light. A first transfer gate is connected between the photo-sensitive element and a first charge conversion element. A second transfer gate is connected between the photo-sensitive element and a second charge conversion element. An output stage outputs a first value related to charge at the first charge conversion element and outputs a second value related to charge at the second charge conversion element. A controller controls operation of the pixel structures and causes a pixel structure.

Abstract: A pixel comprises a pinned photodiode for generating charges in response to incident radiation and a sense node. A transfer gate is positioned between the pinned photodiode and the sense node for controlling transfer of charges to the sense node. A reset switch is connected to the sense node for resetting the sense node to a predetermined voltage. A first buffer amplifier has an input connected to the sense node. A sample stage is connected to the output of the first buffer amplifier and is operable to sample a value of the sense node. A second buffer amplifier has an input connected to the sample stage.

Abstract: An analog-to-digital converter for generating an output digital value equivalent to the difference between a first analog signal level (Vres) and a second analog signal level (Vsig) comprises at least one input for receiving the first analog signal level and the second analog signal level, an input for receiving a ramp signal and an input for receiving at least one clock signal. A set of N counters, where N?2, are arranged to use N clock signals which are offset in phase from one another. A control stage is arranged to enable the N counters based on a comparison of the ramp signal with the first analog signal level (Vres) and the second analog signal level (Vsig). An output stage is arranged to output the digital value which is a function of values accumulated by the N counters during a period when they are enabled.

Abstract: A pixel includes a photo-sensitive element for generating charges in response to incident radiation. A transfer gate is positioned between the photo-sensitive element and a sense node for controlling transfer of charges to the sense node. A reset switch is connected to the sense node for resetting the sense node to a predetermined voltage. A first buffer amplifier has an input connected to the sense node and an output connected to a sample stage operable to sample a value of the sense node. A second buffer amplifier has an input connected to the sample stage. Control circuitry operates the reset switch and causes the sample stage to sample the sense node while the photo-sensitive element is exposed to radiation. An array of pixels is synchronously exposed to radiation. Sampled values for a first exposure period can be read while the photo-sensitive element is exposed for a second exposure period.

Abstract: A pixel structure comprises a photo-sensitive element PPD for generating charges in response to light and a charge conversion element FD. A first transfer gate TX is connected between the photo-sensitive element PPD and the charge conversion element. A charge storage element PG is connected to the photo-sensitive element PPD. The charge storage element PG has a higher charge storage density than the photo-sensitive element PPD. The charge storage element PG is located on the photo-sensitive element PPD side of the first transfer gate TX and is arranged to collect charges generated by the photo-sensitive element PPD during an integration period. The charge storage element can be a photo gate, photodiode or capacitor. Arrangements are provided with, and without, a potential barrier between the photo-sensitive element PPD and the charge storage element PG.

Abstract: A pixel comprises a photo-sensitive element for generating charges in response to incident radiation and a sense node. A transfer gate is positioned between the photo-sensitive element and the sense node for controlling transfer of charges to the sense node. A reset switch is connected to the sense node for resetting the sense node to a predetermined voltage. A first buffer amplifier has an input connected to the sense node. A sample stage is connected to the output of the first buffer amplifier and is operable to sample a value of the sense node. A second buffer amplifier has an input connected to the sample stage. Control circuitry operates the reset switch and causes the sample stage to sample the sense node while the photo-sensitive element is being exposed to radiation. An array of pixels is synchronously exposed to radiation. Sampled values for a first exposure period can be read while the photo-sensitive element is exposed for a second exposure period.

Abstract: An analog-to-digital converter (ADC) generates an output digital value equivalent to the difference between two analog signal values. The ADC 30 receives a first analog signal level, a second analog signal level and a ramp signal. A counter 32 is operable to count in a single direction. A control stage is arranged to enable the counter 32 based on a comparison 19 of the ramp signal with the first analog signal and the second analog signal. A digital value accumulated by the counter during a period when it is enabled forms the output. The ADC can perform the conversion during a single cycle of the ramp signal. The counter 32 can be loaded with a starting digital value representing an exposure level accumulated during a previous exposure period. Techniques are described for reducing the conversion time.

Abstract: A pixel array comprises a plurality of photo-sensitive elements arranged in rows and columns and readout circuitry for reading a value of a photo-sensitive element. Shared readout circuitry is provided for a pair of adjacent photo-sensitive elements. Adjacent instances of the shared readout circuitry are staggered with respect to one another. For a layout having shared readout circuitry for a pair of photo-sensitive elements, adjacent instances of the shared readout circuitry are offset by a horizontal distance of one column and a vertical distance of one row of the array. The shared readout circuitry can serve a pair of adjacent photo-sensitive elements in a row or column of the array, or a pair of photo-sensitive elements which are diagonally adjacent in the array. An improved yield and symmetry results from staggering instances of the shared readout circuitry.

Abstract: A method of manufacturing a backside illuminated image sensor includes providing a start material that has a layer of semiconductor material on a substrate. The layer of semiconductor material has a first face and a second, backside, face. The layer of semiconductor material is processed to form semiconductor devices in the layer adjacent the first face. At least a part of the substrate is removed to leave an exposed face. A passivation layer is formed on the exposed face, the passivation layer having negative fixed charges. The passivation layer can be Al2O3 (Sapphire). The passivation layer can have a thickness less than 5 ?m, advantageously less than 1 ?m, and more advantageously in the range 1 nm-150 nm. Another layer, or layers, can be provided on the passivation layer, including: an anti-reflective layer, a layer to improve passivation, a layer including a color filter pattern, a layer comprising a microlens.

Abstract: An array of active pixels comprises rows of pixels and row select lines for selecting rows of pixels. Each active pixel comprises a buffer amplifier for buffering an output of a photo-sensitive element. An output of the buffer amplifier can be selectively put into a high impedance state, by control of the input of the buffer amplifier, when there is a defect in the row select line for that pixel. This allows other rows, which are defect-free, to remain operating as normal. A disable line can be provided for a row of pixels and each pixel can have a switch connected to the disable line. Alternatively, a first supply line powers a row of pixels. Each pixel comprises a reset switch connected between a photo-sensitive element and the first supply line for resetting the photo-sensitive element.

Abstract: An analog-to-digital converter (ADC) generates an output digital value equivalent to the difference between two analog signal values. The ADC receives a first analog signal level, a second analog signal level and a ramp signal. A counter is operable to count in a single direction. A control stage is arranged to enable the counter based on a comparison of the ramp signal with the first analog signal and the second analog signal. A digital value accumulated by the counter during a period when it is enabled forms the output. The ADC can perform the conversion during a single cycle of the ramp signal. The counter can be loaded with a starting digital value representing an exposure level accumulated during a previous exposure period. Techniques are described for reducing the conversion time.

Abstract: An analog-to-digital converter (ADC) generates an output digital value equivalent to the difference between two analog signal values. The ADC receives a first analog signal level, a second analog signal level and a ramp signal. A counter is operable to count in a single direction. A control stage is arranged to enable the counter based on a comparison of the ramp signal with the first analog signal and the second analog signal. A digital value accumulated by the counter during a period when it is enabled forms the output. The ADC can perform the conversion during a single cycle of the ramp signal. The counter can be loaded with a starting digital value representing an exposure level accumulated during a previous exposure period. Techniques are described for reducing the conversion time.

Abstract: A pixel includes a photo-sensitive element for generating charges in response to incident radiation. A transfer gate is positioned between the photo-sensitive element and a sense node for controlling transfer of charges to the sense node. A reset switch is connected to the sense node for resetting the sense node to a predetermined voltage. A first buffer amplifier has an input connected to the sense node and an output connected to a sample stage operable to sample a value of the sense node. A second buffer amplifier has an input connected to the sample stage. Control circuitry operates the reset switch and causes the sample stage to sample the sense node while the photo-sensitive element is exposed to radiation. An array of pixels is synchronously exposed to radiation. Sampled values for a first exposure period can be read while the photo-sensitive element is exposed for a second exposure period.

Abstract: An analog-to-digital converter generates an output digital value equivalent to the difference between two analog signals. The converter forms part of a set of converters. The converter receives a first analog signal and a second analog signal (Vreset, Vsig) and a ramp signal (Vramp). A clock is dedicated to the converter, or a sub-set of converters. A control stage enables a first counter based on a comparison of the ramp signal with the first analog signal and the second analog signal. The converter can be calibrated by at least one reference signal (Vref1, Vref2) which is common to the set of converters.

Abstract: An analog-to-digital converter (ADC) generates an output digital value equivalent to the difference between two analog signal values. The ADC 30 receives a first analog signal level, a second analog signal level and a ramp signal. A counter 32 is operable to count in a single direction. A control stage is arranged to enable the counter 32 based on a comparison 19 of the ramp signal with the first analog signal and the second analog signal. A digital value accumulated by the counter during a period when it is enabled forms the output. The ADC can perform the conversion during a single cycle of the ramp signal. The counter 32 can be loaded with a starting digital value representing an exposure level accumulated during a previous exposure period. Techniques are described for reducing the conversion time.

Abstract: An analog-to-digital converter (ADC) generates an output digital value equivalent to the difference between two analog signal values. The ADC 30 receives a first analog signal level, a second analog signal level and a ramp signal. A counter 32 is operable to count in a single direction. A control stage is arranged to enable the counter 32 based on a comparison 19 of the ramp signal with the first analog signal and the second analog signal. A digital value accumulated by the counter during a period when it is enabled forms the output. The ADC can perform the conversion during a single cycle of the ramp signal. The counter 32 can be loaded with a starting digital value representing an exposure level accumulated during a previous exposure period. Techniques are described for reducing the conversion time.