Abstract: 2-amino-5-nitropyridinium salts are provided which are usable in non-linear and electrooptics.

Abstract: A liquid crystal display screen including a substrate with conductive addressing columns and conductive blocks, each including a block lengthening piece, a layer of semiconductive material followed by a layer of nonconductive material formed on the addressing columns and conductive blocks, and conductive addressing lines formed on the nonconductive material and each overlapping a block lengthening piece. The block lengthening pieces, the conductive addressing columns, and the conductive addressing lines form addressing transistors. Also, capacitive lines are formed on the nonconductive material and overlap the conductive blocks such that the conductive blocks, the semiconductive material, the nonconductive material, and the capacitive lines form storage capacitors.

Abstract: Control protective circuit, in particular of liquid crystal display screen. The protective circuit includes three transistors making possible the transfer of the voltage to output pin, the resetting of middle point and the resetting of the output. Application to the control of liquid crystal display screens.

Abstract: A method for the automatic analysis of signals by segmentation and classification. To segment the signal, the method is carried out repeatedly by aggregating samples and merging adjacent pulses. Once segmentation has been obtained, classification is carried out. The method has particular application to the analysis of signals with a physiological origin.

Abstract: A circuit for controlling the lines of a display screen and including a t means with a single output is disclosed. The test means includes a single test control line (LCT), a single test output line (LST) and a plurality of sample holders (CEBj) and associated gates (Pj) and switches (Ij). The output voltage of the sample holders is transmitted onto a test output block (ST).

Abstract: A process for exchange of rights between microprocessor cards, wherein multiple keys (K1, K2, . . . ) and varied keys (Ka5, Kb3) are used. A card to be debited calculates a voucher with varied key (Ka5) that the card to be credited reconstitutes. The process has application to electronic payment.

Abstract: Process for optical transmission by wavelength shifting and corresponding system. According to the invention, a wavelength hop corresponding to a mode hop of the laser is performed. The laser (20) is supplied by two currents, which fix the emission wavelengths (.lambda.1, .lambda.2).

Abstract: The method includes only two masking levels. During the second masking, capacitative lines (LC) (dedicated or merged with the addressing lines) are defined which overlap the pixels so as to form the storage capacitors (Cs).Application for display on flat liquid crystal screens.

Abstract: The invention relates to a process of identifying and authenticating data characterizing an individual, by verifying this data use a biometer. The process consists of recording on a memory card the data characterizing the individual owner of the card and of acquiring independently, by a biometer, the data characterizing this individual so as to obtain his imprint to compare it to that of the card and of proceeding to an identical processing of the imprint in the card and in the biometer, so as to establish a parity word and to exchange the parity words obtained by the card and by the biometer to compare them.

Abstract: The generator of the invention includes an initialization circuit (CI) delivering four initialization words (QI, RI, SI, TI), one calculation circuit (CC) composed of four sub-units (SQ, SR, SS, ST) corresponding to four generating polynomials of orders 5, 5, 7 and 7, and finally one output logic circuit (CS) delivering a pseudo-random byte sequence.Application for systems with access control, especially television systems.

Abstract: This process consists of depositing on a III-V or II-VI material (2) a mask layer (6), etching the latter in order to form therein openings (9) facing areas of the material on which epitaxy is to be carried out and then carrying out the epitaxy of the semiconductor layer (14) on said areas in an OMCVD frame by subjecting, at atmospheric pressure, the masked material simultaneously to vapours of chemical species of at least one III or II element and at least one V or VI element, as well as to vapours of HCl or at least one halide of a V or VI element, the elements III and V or II and VI of the chemical species and the halide being those which will form the semiconductor layer, said species being organometallic and/or hydrogen compounds. It is also possible, just prior to the epitaxy stage, to etch (12) the unmasked areas of the material, at atmospheric pressure, in the same frame as for the epitaxy using vapours of at least one halide of a III, V, II or VI element constituting the material to be etched.

Abstract: An apparatus for coding/decoding image signals processes sequential information signals in real time so as to compress the volume of data necessary for representing the corresponding image resulting in a minimum bit rate for transmission of the corresponding image using a transmission network. The coding/decoding apparatus includes a coding arrangement for coding image signals to be transmitted as well as a decoding arrangement for decoding the image signals received. The coding arrangement includes a local image coding loop for images broken down into blocks including a coder incorporating a transformation and quantization arrangement for coding the difference between each block of a local image and the corresponding block of a preceding local image. A decoder of the local image coding loop incorporates a reverse transformation and reverse quantization arrangement for reconstituting each block.

Abstract: The system disclosed includes a light source (12) able to emit an intense, coherent, monochromatic beam, called the control beam, whose frequency is equal to the center optical frequency of one of several frequency multiplexed signals, which has been selected, an optical coupler (14) for coupling the signals and the control beam and an optical switching device (16) having an active material with a non-linear optical response, whose passband is narrower than the intervals separating the frequency band occupied by the selected siganl. The device receives the light from the optical coupler and supplies a beam reproducing the information of the selected signal. The invention can be used in telecommunications.

Abstract: This e.g. Z-propagating, X-cut LiNbO.sub.3 :Ti splitter comprises an alternating delta beta directional coupler (39) able to introduce, in the absence of a voltage between its electrodes, a delta beta variation between its propagation constants, which is (a) independent of the polarization state of the guided lightwave and (b) such that the representative point of the coupler on its control diagram is the center of a segment parallel to the abscissa axis of the reference frame in which the diagram is plotted, and defined by two curves respectively corresponding to parallel states and crossed states of the coupler. Application to integrated optics.

Abstract: An optical detection device with a variable detection threshold. The optical detection device comprises at least one element having a heterostructure on a substrate, the heterostructure incorporating two conducting layers and, between the latter, a semiconducting layer forming a potential barrier with each of the conducting layers is provided. Excited electrons are formed when the heterostructure is illuminated by light radiation, whose energy is at least equal to the detection threshold of the heterostructure. This makes it possible to detect the radiation by an internal photoemission of electrons between one conducting layer and the other. The device also comprises variable biasing of the heterostructure, the biasing making it possible to vary the detection spectrum and threshold of the device. The optical detection device finds particular application to the detection of infrared radiation.