Thomson-csf

Thompson-csf

Jean-Luc Berger

Marc Arques

Jean-Louis Coutures

Yvon Cazaux

Louis Brissot

Roger Benoit-Gonin

Jean-Edgar Picquendar

Sylvain Fontanes

Daniel Woehrn

Daniel Forster

Patrick Descure

Disclosed is a solid state photosensitive device having photosensitive dots, each of which achieves an amplification of the useful signal by means of a transistor obtained by a technology enabling the making photosensitive devices with large areas. To this end, according to the disclosure, each photosensitive diode has at least one photosensitive element that generates electrical charges stored at a point at floating potential, and has a transistor, the control gate of which is connected to the floating point. The transistor thus fulfils an amplifier function, but does not fulfill a photodetection function, so that it can be made of amorphous silicon, amorphous silicon being a material that can be used in thin layers or thin films on large areas.

Photosensitive device of the type with amplification of the signal at

The disclosure concerns matrices of photosensitive elements. To avoid the need for a resetting light source using, as a photosensitive dot, a photodiode in series with a capacitor between a row conductor and a column conductor, it is proposed, according to the invention, to provide for a photosensitive dot comprising three diodes (a photosensitive diode, a reading diode and a resetting diode) connected to a common floating node. In one embodiment, the anode of the photosensitive diode is connected to a row-addressing conductor giving a reading pulse to the selected line; the cathode of the reading diode is connected to the column conductor which collects the useful signal; and the anode of the resetting diode is connected to a second row conductor (which, besides, may be the first conductor of a neighbouring row) which receives a resetting pulse after the reading pulse. In another embodiment, the photosensitive diode is turned back, its cathode being then connected to a row conductor; the resetting diode is simply connected to a reference voltage source.

Photosensitive matrix with three diodes per dot without optical resetting

The disclosure concerns photosensitive matrices and, more precisely, the read circuit connected to each of the output columns of the matrix. To reduce the noise of a transfer from a column to an output register, there is performed, N times successively, a transfer of the charge Qs to be read from the column to an intermediate storage zone, a duplication of this charge and a summation of the duplicated charges Qs*, and a restitution of the charge Qs to the column. If the transfer noises are decorrelated with respect to one another, the overall signal-to-noise ratio is improved in a ratio of N.sup.1/2. A fraction of the sum of the replica charges (for example the mean of the N replica charges) is transmitted to the output and constitutes the output signal of the read circuit.

Low noise reading method and circuit for line transfer photosensitive

The invention relates to a photosensitive matrix (2) permitting the simultaneous acquisition of two images, especially radiological images, and which offers at the same time a maximum sensitivity and a maximum image resolution. The matrix (2) of the invention includes photosensitive points (P1 to P9) disposed in lines and in columns. According to a feature of the invention, each photosensitive point (P1 to 9) includes two photosensitive cells (JA, JB), the first ends (3A, 3B) of which are connected to a same line conductor (L1 to L3), and the second ends (4A, 4B) of which are connected to different column conductors. FIG. 1.

Photosensitive device and image detector including such a device,

A charge transfer device having a first storage gate above a first storage region and a second storage gate above a second storage region. The charge duplicator has a first charge injector having a first passage gate which introduces, below the first storage gate, the reference charge to be duplicated. A second charge injector having a second passage gate is located near the second storage gate. The first storage gate and second storage gate are connected to the two inputs of a voltage comparator, the output of the voltage comparator being connected to the second passage gate. The charge duplicator has a mechanism which initially is used to apply a reference voltage to the two inputs of the voltage comparator, thereby leaving the two inputs and the gates connected to them in a floating state. The voltage comparator outputs a high level or low level, depending on the value of the differential voltage between its inputs. A very steep transition occurs between the two levels, which is as close to zero as possible.

Charge duplicator for charge transfer device

The disclosure concerns matrices of photosensitive elements. To prevent the need for a resetting light source in matrices using, as a photosensitive dot, a photodiode in series with a capacitor between a row conductor and a column conductor, a photosensitive dot is proposed, formed by a photodiode in series with a reading diode between a row conductor and a column conductor, it being possible to put the reading diode into forward or reverse conduction. To read the photoelectrical charges generated, a reading pulse, which makes the reading diode forward conductive, is applied. To then reset the potential of the floating node A, at which the photoelectrical charges accumulate, at a constant starting level, a reverse resetting pulse is applied, thus making the reading diode conductive (but this time in reverse conduction).

Photosensitive matrix with two diodes per dot without specific resetting

The present invention concerns an analysis process of a line transfer photosensitive device. The charge-signal and the charge noise transfers from the columns towards the memory have the same duration and are made by using a same training charge, stored in memory, that must be at least sufficient to allow to pass in high inversion at the beginning of the transfer from the columns towards the memory. The transfers of the charge-signal and the charge-noise from the memory towards the read-out register or the drain have the same duration and are made by using training charges at least sufficient to allow to pass in high inversion at the beginning of the transfer. These training charges are read with the charge-signal or collected with the charge-noise.

Analysis process of a line transfer photosensitive device and operating

The storage capacity of the photosensitive points is increased during the time interval starting after the evacuation of the parasitic charges from the conductive columns to the memory and finishing by the transfer of signal charges from a row of the columns to the memory. Thus, even the overilluminated photosensitive points do not overflow onto the columns.

Process for analyzing a row transfer photosensitive device while

In a light sensitive device having an interline transfer structure comprising a photosensitive matrix of N columns of M photosensitive points each photosensitive point of a single column is connected to a stage of a charge transfer shift register that transfers of the charges of the photosensitive points towards reading register perpendicular to the shift registers, the transfer for signal charges Q.sub.S of the photosensitive points towards the corresponding stages of the shift registers being realized by superimposing a drive charge on the signal charges at the level of the photosensitive points at least sufficient for passing into the high inversion range at the beginning of the transfer. The instant process and apparatus are adapted to be used in the field of solid-state imagery.

Process and apparatus for analyzing a photosensitive device having an

A device for the electric scanning of luminous images. It includes a matrix of N lines and M columns of photosensitive points. A system incorporating a line memory of M points receives in parallel the electric charges supplied by the M points of the same line parasitic charge are removed by diodes. The system insures the injection of the same predetermined quantity of charges between each of the photosensitive points and the output of the device. An output shift register receives in parallel the charges supplied by the line memory and supplies in series a picture scanning electric signal. This device is particularly intended for use in a television camera.

Device for scanning an image in successive lines, utilizing the

The switched-capacitance amplifier comprises n capacitors C.sub.11 to C.sub.1n which are periodically switched in parallel and in series, the n parallel-switched capacitors being charged simultaneously by the same voltage V.sub.E. An amplified voltage n.times.V.sub.E is obtained between the end terminals A and B of the n series-switched capacitors. Periodic switching of the n capacitors in parallel and in series is performed by means of MOS transistors T.sub.11 to T.sub.1(2n-1) and T.sub.21 to T.sub.2(n-1) which operate in the switching mode. The n capacitors and the MOS transistors are integrated on the same semiconductor substrate.

Switched-capacitance amplifier, a switched-capacitance filter and a

An analog device for reading a quantity of electric charge, for example, in a transversal charge transfer filter. The device includes a capacitor and two MOS transistors which are connected in series to the point in the filter where the charge is to be read. The capacitor is connected to the common point of the two transistors which are controlled in phase opposition to insure charging of the capacitor. The capacitor maintains a potential at the charge reading point constant. Any variation in the quantity of charge under an electrode is converted into a variation of potential at the common point and this forms the read signal which is detected by means of a third MOS transistor.

Device for reading a quantity of electric charge

A device for reading a quantity of electric charges arriving at a point B. Two MOS transistors Q2 and Q3 are connected in series and with one terminal to point B. A capacitor C.sub.A is connected to a common point A of the two transistors. A transistor control circuit charges the capacitor C.sub.A from a low potential V.sub.DD. The capacitor C.sub.A and the transistors Q2 and Q3 maintain a constant potential at the point B at the time of charge inflow. This results is a variation of potential at the common point A in accordance with the incoming charges at B. Thus, the variations of potential at point A is a measure of the charges arriving at point B.

Device for reading a quantity of electric charges and charge-filter

Packets of charges representing an electrical signal are injected into a semiconductor substrate by injection means comprising a diode and two electrodes. The charge packets are transferred to an output diode with a well-defined time-delay by means of electrodes which are disposed on the substrate and to which periodic transfer potentials are applied. The output diode also receives samples of the signal to be stored and is connected to an inverter which serves to regenerate and transmit the signal to the injection means.

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Grenoble, France

Jean-Luc Berger