Abstract: The invention concerns active-pixel electronic image sensors. The pixel comprises a photodiode (PH) designed in a semiconductor active layer (12) and maintained at a nil reference potential, and above the active layer an anti-blooming gate (G5) adjacent on one side to the photodiode and on another side to an evacuation drain (22). The sensor comprises means for applying to the anti-blooming gate, during most of the duration of integration, a blocking potential creating beneath the gate a potential barrier of a first height, and, during a series of brief pulses over the duration of integration, an anti-blooming potential creating a potential barrier of a second height, lower than the first. The fact of only applying the anti-blooming voltage during the brief pulses reduces the dark noise induced by tunneling effect by the electric field between gate and photodiode.

Abstract: The invention relates to a method for capturing an image in an image sensor with a matrix of rows and columns of active pixels, powered between a first power supply terminal at zero potential (Vss) and a second power supply terminal at a positive power supply potential (Vdd). Each pixel comprises a photodiode and a gate for transferring the photogenerated charges to a charge storage node. A negative potential (VNEG) is applied to the transfer gate by a charge pump during the charge integration time and it receives a transfer control signal (TRA) common to all the pixels during a transfer time window.

Abstract: The invention proposes a method for distributing a signal to each block Bj of a series of N adjacent blocks of identical design in an electronic circuit. It proposes, in an identical fashion for each of the N blocks, placing a timing delay circuit MUX-DELj on the path for conveying a signal Sc from the input INcj of the block to an internal electrical node Ndj of the block for this signal Sc; providing for the timing delay circuit to supply N delayed signals corresponding to N different timing delays ?f1, . . . ?fj, . . . ?fN separated by an increment of elementary duration ?t that corresponds to the elementary delay ?t for transit of a block introduced into a conductive line; and selecting the delayed signal corresponding to the applicable timing delay according to the block in question, by means of an index signal propagated through the N blocks, and which is incremented or decremented on passage through each block.

Abstract: The invention relates to time delay integration (TDI) image sensors. The sensor includes means for detecting a shift of the sensor with respect to the image. The pixel matrix is divided in the column direction into at least a first and a second sub-matrix (Ma, Mb). On each side of each sub-matrix are arranged groups of additional columns (GRa1, GRb1, GRa2, GRb2). The shifts (Db2?Da2, Db3?Da3, etc.) in relative position of these groups between the first and the second sub-matrices are different from each other and make it possible to detect a relative shift of the sensor during travel. More precisely, the signals originating from groups of columns of same rank associated with the two sub-matrices are compared. The pair of groups that delivers the pair of signals that are closest to each other defines the probable shift of the sensor with respect to the image: this shift is equal to the relative position difference of these two groups.

Abstract: The invention relates to image sensors and more specifically the generation of control signals for pixels and readout circuits. The sequencing circuit which produces these signals comprises: a programmable memory (MEM) containing binary words (M0, M1, M2, etc.) in which each word comprises a group of several bits of position 1 to N, and in which the position i of a bit in a word corresponds to the position i of a respective control signal; a memory controller (CTRL_MEM) for extracting from the memory at a determined rate the words located at successive addresses of the memory from a start address to an end address; and a control signal generation circuit (GEN_TIMING) establishing each control signal of position i from the succession of bits of respective position i that are extracted from the memory by the controller, the control signal reproducing the successive values taken by the bit of position i at the clock rate.

Abstract: In an image sensor, the effective capacitance of the storage node NS of the pixel, which stores the charges (the electrons) collected by the photosensitive element of the pixel, is modified with the aid of a feedback loop 100 which influences the supply VREFP of the follower transistor T3 connected to the storage node, in such a way that the apparent capacitance of the storage node depends on the gain GL of the loop. By modifying the gain, the capacitance of the storage node and therefore the charge/voltage conversion factor, which is inversely proportional to this capacitance, is modified.

Abstract: The invention relates to medical imaging and, more specifically, to intraoral dental radiology. The sensor according to the invention includes a series (SPHx) of detection photodiodes for detecting the arrival of an X-ray flash. The series of photodiodes occupies the location of a central column of the matrix of pixels. The signal of the missing pixel in each row can be reconstructed by interpolating the signals provided by the adjacent pixels of the row. The detection photodiodes are identical to the photodiodes of the active CMOS pixels. They are all electrically connected on one side to a reference potential and on the other side to a detection conductor (CD) extending along the series of photodiodes. This detection conductor is connected to a detection circuit (DX) delivering a signal for triggering the capture of an image when the detected current or the variation in this current exceeds a threshold showing that an X-ray flash has been initiated.

Abstract: A medical radiology system comprises an external x-ray source (1) and a CMOS image sensor (2) that is connected via a USB link (4) by way of USB peripheral of a device (3) for digitally processing the image data of the sensor. A tracking device is placed on the USB link (4) in order to continuously read and decode the data transmitted over this link in a way that is transparent to the device and to the sensor, and to detect, in the transmitted data stream, one particular datum (XAMC=1) representing a signal indicating detection, by the sensor, that a sufficient dose of radiation has been received. On detection of this particular datum, the tracking device sends an electrical signal Stop-X to the radiation source, in order to stop the emission of the radiation. The system is especially suitable for taking dental radiology images with an intra-oral CMOS sensor.

Abstract: In a matrix image sensor, a method of reading a pixel of a column allows two modes of analogue-digital conversion of the voltage level provided by the column: a first mode in which are carried out a single analogue-digital conversion in a nominal conversion time window FCONV, of nominal duration dn and a counting which starts with a ramp of nominal duration dn and stops upon the toggling of the output SCMP of the comparator; and a second mode which provides for multiple conversions by comparison with a ramp of reduced duration dr, in the same nominal conversion time window.

Abstract: The invention relates to the production of images associating with each point of the image a depth, i.e. a distance between the observed point and the camera that produced the image. A light source emits N trains of light pulses. For each train of rank I=1 to N, charge is integrated in a short time slot of length Tint that starts with a temporal offset ti relative to the pulse, this temporal offset representing a journey time of the light pulse between the light source and the sensor after reflection from a point placed a distance di from the sensor. The temporal offset ti is the same for all the light pulses of the ith pulse train but the temporal offsets ti of the N trains are different from one another in order to correspond to various distances relative to the sensor. The charge photogenerated by the pulses of a given train is accumulated; then the accumulated charge is read in order to produce an image of rank i representing the pixels located at the distance di.

Abstract: The invention relates to image sensors, and more particularly to matrix sensors having active pixels in CMOS technology. According to the invention, a method for imaging a scene with a very short integration time, by using a standard image sensor comprising a matrix of pixels, comprising photodiodes, and charge storage nodes, is provided. Two images of the same scene are produced under identical light conditions, one of the images corresponding to integration of charges during a first time interval with a duration Tint and the other image corresponding to a second time interval with a duration T?int longer than Tint, and a difference between these two images is established, representing an image integrated during a time interval T?int?Tint. The light may be provided by a light pulse (IMP). This method may be used for observing points in a scene that lie at a well-determined distance, the brevity of the integration time allowing good precision of the observation distance.

Abstract: The invention relates to image sensors of scanner type observing one image line at a time. According to the invention, only two lines of pixels are used, operating in TDI mode (summation of the charge of two pixels seeing the same image point successively) but using active pixels with a charge-voltage conversion within the pixel. The pixels of like rank of the two lines each use a photodiode and a charge storage node with a transfer gate adjacent to the photodiode and to the storage node for transferring the charge accumulated in the photodiode to the charge storage node. The storage node is shared between the two pixels of like rank, and the charge of the two photodiodes is transferred successively into this node before the reading of the potential taken by the node. The time interval which separates the two charge transfers corresponds substantially to the time which separates the transit of an image line past the first line of pixels and then past the second.

Abstract: The invention relates to time-delay and charge integration image sensors employing active CMOS technology pixels. The sensor comprises N rows of pixels and each pixel of generally square shaped comprises two (though possibly also three or four) photodiodes and charge storage nodes, having means for transferring charges from each photodiode to one or other of the storage nodes. Control of transfer from the photodiodes to one then the other of the storage nodes is carried out in such a way that one storage node receives in succession, during two successive phases of a periodic cycle, the charges from two photodiodes that have seen the same image portion during the two phases. The charges received by one of the storage nodes during the first phase is added to the charges received by the other storage node in the following phase.

Abstract: The invention concerns active-pixel electronic image sensors. The pixel comprises a photodiode (PH) designed in a semiconductor active layer (12) and maintained at a nil reference potential, and above the active layer an anti-blooming gate (G5) adjacent on one side to the photodiode and on another side to an evacuation drain (22). The sensor comprises means for applying to the anti-blooming gate, during most of the duration of integration, a blocking potential creating beneath the gate a potential barrier of a first height, and, during a series of brief pulses over the duration of integration, an anti-blooming potential creating a potential barrier of a second height, lower than the first. The fact of only applying the anti-blooming voltage during the brief pulses reduces the dark noise induced by tunnelling effect by the electric field between gate and photodiode.

Abstract: The invention relates to matrix image sensors organized into pixel rows and columns, and more specifically to image sensors produced with active pixels in MOS technology. The matrix is organized into groups of at least two pixels with means for grouping the charges engendered in the two pixels into one pixel, with the aim of improving sensitivity. Provision is made for at least one gate for temporarily storing charges, of dissymmetric form, arranged between the photodiode of the first pixel and the photodiode of the second pixel, and means for applying to the temporary storage gate a succession of potentials that allow prohibition first of all of the passage of charges between the first and second photodiodes during the charge integration period, then collection, under the gate, of the charges accumulated in the photodiodes, then discharge of these charges only into the second photodiode, on account of the dissymmetry of the gate. The charges grouped in this way in a single photodiode are read in the pixel.

Abstract: In the field of image sensors, more particularly time-delay integration linear sensors or TDI sensors, a sensor comprises rows of photodiodes alternating with rows of gates adjacent to the photodiodes. The gates are asymmetric, adjacent on one side to a photodiode and having, on the other side, narrow gate fingers extending toward another photodiode. Owing to their very narrow width, the fingers endow the transfer of charges with a directionality. Between two successive photodiodes there are two gates, the two being adjacent to the two photodiodes, the first having its narrow fingers turned toward the first photodiode, the second having its narrow fingers turned toward the second photodiode. The direction of transfer of the charges in the sensor may be chosen by neutralizing either the first gate or the second gate, the other gate receiving alternating potentials allowing the transfer of charges from one photodiode to the other.

Abstract: This description relates to active-pixel image sensors. Each pixel includes, at the surface of a semiconductor active layer, a photodiode region, a charge storage node and a transfer structure for transferring charges from the photodiode to the storage node after a charge integration time for charges generated by the light in the photodiode. The transfer structure includes a first transfer gate adjacent to the photodiode, a second transfer gate adjacent to the storage node, and an electron-multiplication amplifying structure located between the first and second transfer gates. The amplifying structure includes two separate accelerating gates and an intermediate diode region at a fixed surface potential, located between the two accelerating gates. A succession of alternating high and low potentials is applied to the accelerating gates while the charges are in transit in the transfer structure, before they are transferred to the storage node.

Abstract: The invention relates to digital-to-analog converters for converting current. The converter includes a pair of differential branches with two transistors controlled by a digital register activated at a clock frequency, and two resistive loads receiving the currents of the differential branches to produce a differential electrical signal representing the analog result of the conversion. The converter includes a dual switching circuit for the currents of the differential branches: a first switching circuit enables the transmission of the currents of the differential branches toward the loads for 70% to 95% of the clock period and shunts these currents outside the loads for the rest of the time; a second switching circuit alternately and symmetrically makes a direct link followed by a cross link between the differential branches and the loads.

Abstract: The invention relates to an image sensor with N rows of P active photosensitive pixels using MOS technology. The sensor comprises digitizing circuits organized with N rows of P processing circuits, each processing circuit of row rank i and of column rank j comprising a respective sampler for carrying out a correlated double sampling of the signals present on a column conductor of rank j and corresponding to the observation of an image dot over the same integration time for all the rows, and an analog-digital conversion means in order to supply digital values of the analog signals sampled. The sensor is particularly suited to operating in TDI (image scanning and integration) mode.