Abstract: Black level calibration methods and systems are generally disclosed. According to one embodiment of the present invention, a method of calibrating a black level signal in a frame includes performing an iteration of averaging a first set of digital values corresponding to a first set of adjusted black level signals associated with a first set of black pixels of the frame, determining whether an average value based on the first set of digital values has reached a target black level, determining a calibration offset based on a difference between the average value and the target black level and an accumulator step, converting the calibration offset to an analog signal, generating a calibration signal based on the analog signal for a second set of black pixels of the frame, and repeating the iteration for the frame until a predetermined condition is determined to have been met.

Abstract: A method for forming an image sensing device is disclosed. An epitaxy layer having the first conductivity type is formed on a substrate, wherein the epitaxy layer comprises a first pixel area corresponding to a first incident light, a second pixel area corresponding to a second incident light, and a third pixel area corresponding to a third incident light. A first deep well is formed in a lower portion of the epitaxy layer for reducing pixel-to-pixel talk of the image sensing device. A second deep well is formed in a lower portion of the epitaxy layer.

Abstract: An image sensing device is disclosed, including an epitaxy layer having the a conductivity type, including a first pixel area corresponding to a first incident light, a second pixel area corresponding to a second incident light, and a third pixel area corresponding to a third incident light, wherein the wavelength of the first incident light is longer than that of the second incident light and the wavelength of the second incident light is longer than that of the third incident light. A photodiode is disposed in an upper portion of the epitaxy layer, and a first deep well for reducing pixel-to-pixel talk of the image sensing device is disposed in a lower portion of the epitaxy layer in the second pixel area and the third pixel area, wherein at least a portion of the epitaxy layer in first pixel area does not include the first deep well.

Abstract: A process and structure of a backside illumination (BSI) image sensor are disclosed. An n-type doped region is formed in a substrate, and a transfer gate is formed on top of the semiconductor substrate. A p-type doped region is formed in the n-type doped region either using the transfer gate as a mask or is non-self aligned formed.

Abstract: A signal chain of an imaging system is disclosed. The system includes three circuit stages. The first circuit stage includes a programmable gain amplifier (PGA) and a black level compensation (BLC) circuit that form a BLC loop. The second circuit stage includes an analog-to-digital converter (ADC), where a dark signal offset is added at an input of the ADC. The third circuit stage includes a digital gain circuit and a digital loop that makes a final output of the imaging system settle on a target level in the BLC mode.

Abstract: A process and structure of a back side illumination (BSI) image sensor are disclosed. An n-type doped region is formed in a substrate, and a transfer gate is formed on top of the semiconductor substrate. A p-type doped region is formed in the n-type doped region either using the transfer gate as a mask or is non-self aligned formed.

Abstract: A pixel circuit of a CMOS image sensor is disclosed. At least two transfer transistors are configured to transfer integrated light signals of corresponding photodetectors to a first node. A reset transistor is configured to reset the first node to a predetermined reset voltage of a second node, and a source follower is configured to buffer the integrated light signals. In one embodiment, a capacitor is further connected between the first node and the second node to minimize influence of the effective capacitance including capacitance of a floating diffusion region and parasitic capacitance due to the photodetector and the transfer transistor.

Abstract: An image sensing device is disclosed, including an epitaxy layer having the a conductivity type, including a first pixel area corresponding to a first incident light, a second pixel area corresponding to a second incident light, and a third pixel area corresponding to a third incident light, wherein the wavelength of the first incident light is longer than that of the second incident light and the wavelength of the second incident light is longer than that of the third incident light. A photodiode is disposed in an upper portion of the epitaxy layer, and a first deep well for reducing pixel-to-pixel talk of the image sensing device is disposed in a lower portion of the epitaxy layer in the second pixel area and the third pixel area, wherein at least a portion of the epitaxy layer in first pixel area does not include the first deep well.

Abstract: A scheme is provided that enhances the dynamic range performance of images via multiple readouts during one exposure. The readout process circuit structure includes at least an analog-to-digital converter (ADC). The analog-to-digital converter converts analog data generated from an image sensor into digital data, allowing sub-frame readouts for improving a dynamic range of the image sensor. Additionally, methods of partial digitization (not a full number of bits) and image array are provided.

Abstract: A process and structure of a back side illumination (BSI) image sensor are disclosed. An n-type doped region is formed in a substrate, and a transfer gate is formed on top of the semiconductor substrate. A p-type doped region is formed in the n-type doped region either using the transfer gate as a mask or is non-self aligned formed.

Abstract: Black level calibration methods and systems are generally disclosed. According to one embodiment of the present invention, a method of calibrating a black level signal in a frame includes performing an iteration of averaging a first set of digital values corresponding to a first set of adjusted black level signals associated with a first set of black pixels of the frame, determining whether an average value based on the first set of digital values has reached a target black level, determining a calibration offset based on a difference between the average value and the target black level and an accumulator step, converting the calibration offset to an analog signal, generating a calibration signal based on the analog signal for a second set of black pixels of the frame, and repeating the iteration for the frame until a predetermined condition is determined to have been met.

Abstract: A signal chain of an imaging system is disclosed. The system includes three circuit stages. The first circuit stage includes a programmable gain amplifier (PGA) and a black level compensation (BLC) circuit that form a BLC loop. The second circuit stage includes an analog-to-digital converter (ADC), where a dark signal offset is added at an input of the ADC. The third circuit stage includes a digital gain circuit and a digital loop that makes a final output of the imaging system settle on a target level in the BLC mode.

Abstract: An electronic image sensor with a pixel array of a plurality of active pixels is provided. Each of the active pixels includes: a photo detector, providing a sensing node for producing a signal based on an amount of light incident thereon; a storing node for storing a plurality of photo-generated charges according to the signal; a first controllable potential barrier between the sensing node and the storing node; an outputting node; and a second controllable potential barrier between the storing node and the outputting node, wherein each of the sensing node, the storing node and the sampling node is not overlapped.

Abstract: A scheme is provided that enhances the dynamic range performance of images via multiple readouts during one exposure. The readout process circuit structure includes at least an analog-to-digital converter (ADC). The analog-to-digital converter converts analog data generated from an image sensor into digital data, allowing sub-frame readouts for improving a dynamic range of the image sensor. Additionally, methods of partial digitization (not a full number of bits) and image array are provided.

Abstract: A pixel circuit of a CMOS image sensor is disclosed. At least two transfer transistors are configured to transfer integrated light signals of corresponding photodetectors to a first node. A reset transistor is configured to reset the first node to a predetermined reset voltage of a second node, and a source follower is configured to buffer the integrated light signals. In one embodiment, a capacitor is further connected between the first node and the second node to minimize influence of the effective capacitance including capacitance of a floating diffusion region and parasitic capacitance due to the photodetector and the transfer transistor.

Abstract: One embodiment of the present invention describes a pixel circuit that comprises at least one photodiode, a first transistor coupled between the photodiode and a floating diffusion node, a second transistor coupled between the floating diffusion node and a modifiable driving voltage signal, and a third transistor having a gate coupled to the floating diffusion node, a source coupled to a signal output, and a drain coupled to a constant voltage. Another embodiment of the present invention provides a method for driving the pixel circuit, which comprises resetting the photodiode and the floating diffusion node, exposing the photodiode to light to accumulate charges, selecting the pixel circuit by switching the driving voltage signal from a first voltage level to a second voltage level, retrieving a reference voltage from the selected pixel circuit, and retrieving an image signal from the selected pixel circuit corresponding to the accumulated charges.

Abstract: A black level calibration (BLC) system is disclosed. A readout chain receives and amplifies dark signal, and generates corresponding digital output. A level integrator performs integration of calibration levels in multiple steps according to the digital output, thereby achieving wide calibration range.

Abstract: An electronic device is provided such as a programmable rise/fall time control circuit, for example, that delivers a continuous and near linear rising/falling slope of a control signal, with programmability that can be implemented in future CMOS image sensor devices. This device includes a programmability block for reset or transfer gate signals. The programmability block includes two inputs: an input bias current and a signal from the control bits. The programmability block further includes two similar internal circuit blocks, one for generating a fall time control signal, and one for generating a rise time control signal. Additionally the programmability block includes two outputs; a fall time control signal, and a rise time control signal. The device further includes a reset or transfer gate buffer configured as an inverter. The reset or transfer gate buffer includes three input signals: The fall time control signal and rise time control signal from the programmability block, and an INT Reset signal.